WEBVTT 00:00:00.000 --> 00:00:02.020 Welcome back to The Deep Dive, the show where 00:00:02.020 --> 00:00:04.339 we take a complex pile of information, a stack 00:00:04.339 --> 00:00:07.379 of sources, articles, research notes, and, well, 00:00:07.519 --> 00:00:10.679 we distill it all into pure, fascinating knowledge. 00:00:10.939 --> 00:00:13.359 And today we are really getting into one of the 00:00:13.359 --> 00:00:15.500 big ones. We are. We're not just visiting a destination. 00:00:15.820 --> 00:00:18.859 We're trying to unearth an enigma that has, you 00:00:18.859 --> 00:00:21.320 know, captivated the world for over a century. 00:00:21.440 --> 00:00:23.820 We are peeling back the moss and the mystery 00:00:23.820 --> 00:00:26.379 of the legendary Inca citadel. We're talking 00:00:26.379 --> 00:00:29.120 about Machu Picchu. Yeah. And it is so much more 00:00:29.120 --> 00:00:31.679 than just a picture on a postcard. It's this 00:00:31.679 --> 00:00:37.020 iconic symbol of ingenuity, isolation and a mystery 00:00:37.020 --> 00:00:39.240 that just keeps going. It was even designated 00:00:39.240 --> 00:00:41.219 one of the new seven wonders of the world back 00:00:41.219 --> 00:00:44.469 in 2007. Right. But more than that, it's a masterpiece 00:00:44.469 --> 00:00:47.590 of urban planning and engineering that was, and 00:00:47.590 --> 00:00:49.369 this is the key part, it was literally built 00:00:49.369 --> 00:00:51.609 upon the most challenging volatile terrain you 00:00:51.609 --> 00:00:53.789 can imagine. Okay, let's unpack this. For you, 00:00:53.810 --> 00:00:55.750 the listener, we've gathered a fantastic staff 00:00:55.750 --> 00:00:58.030 of sources today. We're trying to move beyond 00:00:58.030 --> 00:01:00.450 the standard tourist brochure. We're looking 00:01:00.450 --> 00:01:02.789 at 16th century ethno -historical documents, 00:01:03.450 --> 00:01:05.829 Hiram Bingham's own kind of contradictory field 00:01:05.829 --> 00:01:08.829 notes. We've also got modern archaeological reports, 00:01:09.189 --> 00:01:11.909 detailed geological studies, and this is critical. 00:01:12.109 --> 00:01:15.329 cutting -edge radiocarbon dating that is forcing 00:01:15.329 --> 00:01:18.250 historians to redraw their timelines. Exactly. 00:01:18.450 --> 00:01:21.150 Our mission today is pretty clear. We want to 00:01:21.150 --> 00:01:23.790 move past that romanticized idea of the lost 00:01:23.790 --> 00:01:26.909 city of the Incas and really understand the facts, 00:01:27.049 --> 00:01:30.150 the why and the how behind this site's creation 00:01:30.150 --> 00:01:33.280 and, you know, its surprisingly brief life. We 00:01:33.280 --> 00:01:35.900 are diving into its contested chronology, the 00:01:35.900 --> 00:01:37.920 brilliant structural engineering that really 00:01:37.920 --> 00:01:40.959 defies both gravity and geology. And the intense, 00:01:41.040 --> 00:01:43.879 continuous modern challenge of preserving this 00:01:43.879 --> 00:01:46.239 vast historic sanctuary. And just to situate 00:01:46.239 --> 00:01:47.819 ourselves, because the location is everything 00:01:47.819 --> 00:01:50.620 here, we are focusing on a 15th century Inca 00:01:50.620 --> 00:01:53.780 yacta. Right, and the Quechua term, yacta, it 00:01:53.780 --> 00:01:55.859 isn't just a city. It refers to a specialized 00:01:55.859 --> 00:01:58.450 settlement, maybe even a sacred center. It's 00:01:58.450 --> 00:02:00.469 situated in the eastern cordillera of southern 00:02:00.469 --> 00:02:04.209 Peru, sitting at a truly breathtaking 2 ,430 00:02:04.209 --> 00:02:08.849 meters. That's roughly 7 ,970 feet above a deep 00:02:08.849 --> 00:02:11.090 canyon carved by the Urubamba River. I mean, 00:02:11.110 --> 00:02:13.330 that altitude alone represents a triumph of logistics, 00:02:13.509 --> 00:02:15.569 let alone the complex city they built there. 00:02:15.669 --> 00:02:18.530 Sure. Exactly. The location wasn't just impressive. 00:02:18.669 --> 00:02:21.189 It was immediately part of the political statement 00:02:21.189 --> 00:02:24.189 of imperial power. So we need to dissect not 00:02:24.189 --> 00:02:26.550 just the stones and the architecture, but the 00:02:26.550 --> 00:02:29.069 people who lived there, the rituals they performed, 00:02:29.090 --> 00:02:31.349 and the whole political context that allowed 00:02:31.349 --> 00:02:34.430 such a marvel to exist for a brief but spectacular 00:02:34.430 --> 00:02:37.810 moment in the Inca Empire. So let's start where 00:02:37.810 --> 00:02:41.050 any good historical analysis begins, the beginning. 00:02:42.599 --> 00:02:44.659 Traditionally, when we talk about Machu Picchu's 00:02:44.659 --> 00:02:48.439 origin, we tie it directly to this massive expansionist 00:02:48.439 --> 00:02:51.319 phase of the Inca Empire under one key figure. 00:02:51.870 --> 00:02:54.870 the ninth Sapa Inca, Pachacuti Inca Yupanqui. 00:02:54.969 --> 00:02:57.289 That's the consensus, yeah. It's derived from 00:02:57.289 --> 00:02:59.069 the documentary evidence, you know, the early 00:02:59.069 --> 00:03:01.870 Spanish historical reconstructions. These models 00:03:01.870 --> 00:03:04.189 place the start of construction around 1450, 00:03:04.270 --> 00:03:06.849 which is roughly a decade after Pachacuti's takeover 00:03:06.849 --> 00:03:08.729 and the rapid expansion of the empire. Right. 00:03:08.949 --> 00:03:11.270 The theory long held that he ordered this seasonal 00:03:11.270 --> 00:03:13.770 royal retreat, or maybe an estate, after his 00:03:13.770 --> 00:03:16.469 successful conquest of the middle and lower Urubamba 00:03:16.469 --> 00:03:18.740 region. The idea was that it was meant to be 00:03:18.740 --> 00:03:20.840 a prestigious destination for his court. And 00:03:20.840 --> 00:03:22.419 the work was thought to have maybe continued 00:03:22.419 --> 00:03:25.379 under his son. Potentially, yes, under his successor, 00:03:25.719 --> 00:03:29.020 Tupac Inca Yupanqui. That seemed like a neat 00:03:29.020 --> 00:03:31.960 and tidy narrative, an imperial villa built by 00:03:31.960 --> 00:03:34.460 the emperor who conquered the territory. But 00:03:34.460 --> 00:03:36.120 here's where it gets really, really interesting, 00:03:36.199 --> 00:03:38.879 because that traditional consensus tends to get 00:03:38.879 --> 00:03:41.939 refined, if not entirely overthrown, by modern 00:03:41.939 --> 00:03:44.750 technology. Precisely. The documentary model 00:03:44.750 --> 00:03:47.210 gave us a fixed starting point, but it was based 00:03:47.210 --> 00:03:49.370 on oral traditions that were recorded after the 00:03:49.370 --> 00:03:51.930 conquest. So not exactly firsthand accounts? 00:03:52.090 --> 00:03:55.689 Not at all. But a landmark 2021 study led by 00:03:55.689 --> 00:03:57.789 researchers, including Richard Berger at Yale, 00:03:57.949 --> 00:04:00.590 provided a significant source -based refinement 00:04:00.590 --> 00:04:04.569 using hard science. They analyzed 26 highly sensitive 00:04:04.569 --> 00:04:08.310 AMS, that's accelerator mass spectrometry radiocarbon 00:04:08.310 --> 00:04:10.590 measurements, from human remains recovered during 00:04:10.590 --> 00:04:13.479 the early 20th century excavations. And the specific 00:04:13.479 --> 00:04:16.000 date nugget they pulled out shifted the timeline 00:04:16.000 --> 00:04:18.680 back, right? A lot. So if the traditional timeline 00:04:18.680 --> 00:04:21.600 places Pachacuti's big expansion around 1450, 00:04:21.839 --> 00:04:24.860 how significant is a 1420 start date? Does that 00:04:24.860 --> 00:04:27.000 fundamentally change who we think founded the 00:04:27.000 --> 00:04:29.959 site? It's a huge shift, and it directly challenges 00:04:29.959 --> 00:04:32.699 that historical narrative. This modern dating 00:04:32.699 --> 00:04:35.300 suggests that Machu Picchu was occupied earlier 00:04:35.300 --> 00:04:38.480 than historians previously assumed. It places 00:04:38.480 --> 00:04:42.060 the initial period of use roughly between circa 00:04:42.060 --> 00:04:45.899 1420 and 1530. So that pushes the initial occupation 00:04:45.899 --> 00:04:49.860 back at least two decades. At least, potentially 00:04:49.860 --> 00:04:52.399 even three, before the traditional models place 00:04:52.399 --> 00:04:55.100 Pachacuti's rise to power and the conquest of 00:04:55.100 --> 00:04:57.759 the Urubamba region. So what does this new timeline 00:04:57.759 --> 00:04:59.920 actually mean for the empire? Does it suggest 00:04:59.920 --> 00:05:02.920 a pre -Pachacuti builder or does it force us 00:05:02.920 --> 00:05:05.620 to redate the conquest itself? Well, it forces 00:05:05.620 --> 00:05:08.220 a reassessment of Inca expansion dynamics. That 00:05:08.220 --> 00:05:11.100 1420 date is a major challenge. It suggests two 00:05:11.100 --> 00:05:13.800 possibilities. Either the construction and use 00:05:13.800 --> 00:05:16.000 of the site began before Pachacuti became the 00:05:16.000 --> 00:05:17.939 dominant unifying force. So maybe it started 00:05:17.939 --> 00:05:20.720 as a smaller regional site that he later expanded? 00:05:20.939 --> 00:05:23.540 That's one idea. Or, and this is maybe more likely, 00:05:23.699 --> 00:05:25.939 the military conquest of the Uruvamba Valley 00:05:25.939 --> 00:05:28.540 that fueled Pachacuti's rise just happened much 00:05:28.540 --> 00:05:30.600 earlier in his career than we previously modeled. 00:05:30.860 --> 00:05:33.379 So either way, the Inca were there earlier than 00:05:33.379 --> 00:05:35.680 the Spanish recorded histories let on. Exactly. 00:05:35.759 --> 00:05:38.459 It refines our understanding of Inca imperial 00:05:38.459 --> 00:05:40.959 timing, showing their reach was established earlier. 00:05:41.389 --> 00:05:44.329 And yet for such a monumental, logistically insane 00:05:44.329 --> 00:05:47.470 project, it had a surprisingly brief existence, 00:05:47.790 --> 00:05:51.550 only about 80 years of active imperial use. It 00:05:51.550 --> 00:05:53.850 was a spectacular but very short -lived endeavor. 00:05:54.149 --> 00:05:56.790 The abandonment context is tragic and swift. 00:05:57.050 --> 00:06:01.550 It happened sometime between 1532 and 1565. Right 00:06:01.550 --> 00:06:03.949 in the middle of the Spanish conquest. It was. 00:06:04.439 --> 00:06:06.980 And while the collapse of formal Inca rule certainly 00:06:06.980 --> 00:06:09.459 played a role, the sources suggest that the rapid 00:06:09.459 --> 00:06:12.240 spread of diseases introduced by Europeans, specifically 00:06:12.240 --> 00:06:15.240 smallpox, may have decimated the support population 00:06:15.240 --> 00:06:17.819 before the Spanish military ever even arrived 00:06:17.819 --> 00:06:19.899 in the immediate area. So the site just couldn't 00:06:19.899 --> 00:06:22.100 sustain itself. It couldn't. The political structure 00:06:22.100 --> 00:06:24.839 crumbled. Its necessary labor force vanished. 00:06:25.060 --> 00:06:27.319 And because the site was so high up and logistically 00:06:27.319 --> 00:06:29.319 challenging, it just never became a target for 00:06:29.319 --> 00:06:31.839 the Spanish in the way Cusco or other major cities 00:06:31.839 --> 00:06:34.240 did. That explains why it became a lost city. 00:06:34.279 --> 00:06:36.300 Not because the Spanish destroyed it, but because 00:06:36.300 --> 00:06:38.740 the people who ran it died or dispersed, leaving 00:06:38.740 --> 00:06:42.040 it to the jungle. Precisely. It was lost to history, 00:06:42.180 --> 00:06:45.079 but, and this is an important point, it was never 00:06:45.079 --> 00:06:47.439 lost to the local Quechua families who maintained 00:06:47.439 --> 00:06:49.920 small settlements there. Which brings us to a 00:06:49.920 --> 00:06:52.540 major point of confusion for tourists and scholars 00:06:52.540 --> 00:06:56.100 alike. The name. We all call it Machu Picchu, 00:06:56.220 --> 00:06:58.500 but what does that name actually signify? And 00:06:58.500 --> 00:07:01.500 was that the original name the Inca used? Let's 00:07:01.500 --> 00:07:04.100 unpack that. The etymology is pretty straightforward 00:07:04.100 --> 00:07:07.920 in the Quechua language. Machu means old, or 00:07:07.920 --> 00:07:11.000 old person. While Huayna often spelled H -U -A 00:07:11.000 --> 00:07:14.620 -Y -N -A means young. And Picchu? Picchu translates 00:07:14.620 --> 00:07:18.550 to peak, summit, or maybe pyramid. So the common 00:07:18.550 --> 00:07:20.750 name, Maichu Picchu, translates literally to 00:07:20.750 --> 00:07:23.629 old mountain or old peak, referring to the specific 00:07:23.629 --> 00:07:25.550 mountain saddle on which the settlement sits. 00:07:25.769 --> 00:07:28.009 And the smaller pointy peak next to it is Huayna 00:07:28.009 --> 00:07:30.490 Picchu. The young peak. Exactly. But there's 00:07:30.490 --> 00:07:33.089 a major naming controversy swirling around here 00:07:33.089 --> 00:07:35.350 based on recent historical findings that suggest 00:07:35.350 --> 00:07:36.970 we might be calling the site by the wrong name 00:07:36.970 --> 00:07:40.410 entirely. Absolutely. The same 2021 research 00:07:40.410 --> 00:07:43.110 that refined the chronology also provided some 00:07:43.110 --> 00:07:46.620 really strong esno -historical evidence. Researchers 00:07:46.620 --> 00:07:49.139 reviewed late 16th century documents and found 00:07:49.139 --> 00:07:51.920 consistent references from indigenous individuals 00:07:51.920 --> 00:07:56.139 who mentioned returning to Huayna Picchu. Referring 00:07:56.139 --> 00:07:58.220 to the main settlement, not just the little peak. 00:07:58.560 --> 00:08:00.339 Exactly. They were referring to the main settlement. 00:08:00.740 --> 00:08:02.899 It seems the site may have been named for that 00:08:02.899 --> 00:08:06.259 smaller, more visually distinctive peak, or perhaps 00:08:06.259 --> 00:08:09.040 it was just called Picchu, the peak. So if local 00:08:09.040 --> 00:08:11.540 Quechua speakers knew it as Huayna Picchu or 00:08:11.540 --> 00:08:14.420 simply Picchu, how did the entire world end up 00:08:14.420 --> 00:08:17.540 calling it Machu Picchu? That association and 00:08:17.540 --> 00:08:19.300 the resulting international cementing of the 00:08:19.300 --> 00:08:22.420 name Machu Picchu stems almost entirely from 00:08:22.420 --> 00:08:25.300 Hiram Bingham's 1911 publications and his subsequent 00:08:25.300 --> 00:08:28.079 narrative. Even though he acknowledged the local 00:08:28.079 --> 00:08:30.639 names for both peaks, his field notes, his early 00:08:30.639 --> 00:08:33.100 maps, and especially his later bestselling book, 00:08:33.279 --> 00:08:35.659 they all popularized the name Machu Picchu globally. 00:08:36.029 --> 00:08:37.909 It seems like a classic case of the narrative 00:08:37.909 --> 00:08:40.309 of the scientific discoverer overriding local 00:08:40.309 --> 00:08:43.470 knowledge. It is. Bingham was looking for a completely 00:08:43.470 --> 00:08:46.110 different place, the long lost capital of Vitkos. 00:08:46.250 --> 00:08:49.009 By focusing his documentation and all the publicity 00:08:49.009 --> 00:08:51.970 on the Machu Picchu location, he basically solidified 00:08:51.970 --> 00:08:54.629 that name for the whole world. It's a reminder 00:08:54.629 --> 00:08:57.370 that geography and language, even in a lost city, 00:08:57.509 --> 00:08:59.929 are often shaped by who gets to tell the story. 00:09:00.409 --> 00:09:02.789 The brief 80 -year existence of the city is made 00:09:02.789 --> 00:09:05.230 even more miraculous by the complexity of the 00:09:05.230 --> 00:09:07.330 how. I mean, it's a feat of civil engineering 00:09:07.330 --> 00:09:10.409 that just beggars belief. We're talking about 00:09:10.409 --> 00:09:14.009 building this complex, monumental city on a narrow 00:09:14.009 --> 00:09:17.110 saddle between two peaks floating 450 meters 00:09:17.110 --> 00:09:19.350 that's nearly 1 ,500 feet above the river canyon. 00:09:19.590 --> 00:09:22.870 This location is not only remote, it's geologically 00:09:22.870 --> 00:09:25.909 terrifying. It is a geological marvel made possible 00:09:25.909 --> 00:09:28.570 only by incredible human ingenuity. Shifting 00:09:28.570 --> 00:09:30.669 focus now to the construction, we have to talk 00:09:30.669 --> 00:09:33.029 about the classical Inca dry masonry. It's the 00:09:33.029 --> 00:09:35.470 hallmark of the site and really the key to its 00:09:35.470 --> 00:09:37.909 survival against the elements. We often hear 00:09:37.909 --> 00:09:40.470 that the stones fit together so tightly you can't 00:09:40.470 --> 00:09:42.190 slide a piece of paper between them and there's 00:09:42.190 --> 00:09:44.710 no mortar. For a non -engineer like me, that 00:09:44.710 --> 00:09:47.710 sounds like a liability. Why is that lack of 00:09:47.710 --> 00:09:50.570 mortar the key to stability in an earthquake 00:09:50.570 --> 00:09:53.009 zone? Well, it's this ingenious inversion of 00:09:53.009 --> 00:09:55.700 stability. That precision, the shaping and fitting 00:09:55.700 --> 00:09:58.019 of massive granite blocks quarried directly on 00:09:58.019 --> 00:10:01.799 site, is called ashlar masonry. Because the blocks 00:10:01.799 --> 00:10:04.299 interlock so perfectly, they distribute weight 00:10:04.299 --> 00:10:07.259 and force evenly, making them stable under normal 00:10:07.259 --> 00:10:09.960 conditions. Okay. But crucially, the lack of 00:10:09.960 --> 00:10:12.759 mortar allows the stones a minuscule degree of 00:10:12.759 --> 00:10:16.019 movement. a kind of flexibility during seismic 00:10:16.019 --> 00:10:18.259 activity. Instead of cracking or shattering, 00:10:18.419 --> 00:10:20.639 the walls can essentially dance slightly during 00:10:20.639 --> 00:10:22.720 a tremor, transferring the force effectively 00:10:22.720 --> 00:10:24.799 and then settling right back into place. And 00:10:24.799 --> 00:10:26.759 the structural resilience was not accidental 00:10:26.759 --> 00:10:29.720 because the geological context here is just fascinating. 00:10:29.980 --> 00:10:31.820 Not accidental at all. And what's so fascinating 00:10:31.820 --> 00:10:34.740 is the finding that Machu Picchu was built intentionally 00:10:34.740 --> 00:10:37.679 over two major earthquake fault lines. Wait, 00:10:37.759 --> 00:10:40.000 wait. They built it on a fault line, not around 00:10:40.000 --> 00:10:42.860 one. That seems like the definition of an unstable 00:10:42.860 --> 00:10:45.960 foundation for a large city. It seems completely 00:10:45.960 --> 00:10:48.539 counterintuitive. But that's the brilliant inversion. 00:10:49.480 --> 00:10:51.879 Geologists suggest this location was intentional 00:10:51.879 --> 00:10:54.259 because the fault lines caused the bedrock to 00:10:54.259 --> 00:10:57.539 be highly fractured. Ah, so the rock was already 00:10:57.539 --> 00:11:00.299 broken up for them. Exactly. This meant that 00:11:00.299 --> 00:11:02.179 the massive amounts of granite required for the 00:11:02.179 --> 00:11:04.299 construction were already broken up into manageable 00:11:04.299 --> 00:11:07.379 pieces, easily available for quarrying and shaping. 00:11:07.840 --> 00:11:10.240 They didn't have to carve perfect blocks out 00:11:10.240 --> 00:11:13.019 of solid, stable rock. The earth had done the 00:11:13.019 --> 00:11:15.940 initial work for them. One researcher even called 00:11:15.940 --> 00:11:18.700 it an empire of fractured rocks, highlighting 00:11:18.700 --> 00:11:21.419 how the Inca exploited geological weakness for 00:11:21.419 --> 00:11:23.980 material gain. So they turned a geological weakness 00:11:23.980 --> 00:11:26.659 into a logistical strength. They chose the location 00:11:26.659 --> 00:11:28.399 because the fractured rock made the material 00:11:28.399 --> 00:11:30.799 easier to access, and then they engineered the 00:11:30.799 --> 00:11:33.039 masonry to withstand the inevitable earthquakes 00:11:33.039 --> 00:11:35.929 that the fracturing suggested. That's an incredible 00:11:35.929 --> 00:11:39.149 level of adaptive genius. It's astounding. What 00:11:39.149 --> 00:11:41.909 specific design features did they use to stabilize 00:11:41.909 --> 00:11:44.429 these structures? They engineered in flexibility 00:11:44.429 --> 00:11:46.750 through shape. For instance, if you look at the 00:11:46.750 --> 00:11:49.309 architecture, the doors and windows are trapezoidal. 00:11:49.429 --> 00:11:51.610 Meaning they narrow from the bottom to the top. 00:11:51.750 --> 00:11:54.929 Right. And that shape, narrowing upward, is inherently 00:11:54.929 --> 00:11:57.230 much more resistant to the lateral and shear 00:11:57.230 --> 00:11:59.690 forces generated during an earthquake than a 00:11:59.690 --> 00:12:02.460 standard perpendicular rectangle. It's brilliant. 00:12:02.639 --> 00:12:04.620 It turns the architecture itself into a safety 00:12:04.620 --> 00:12:07.679 valve. What other details did they include to 00:12:07.679 --> 00:12:09.960 keep the whole city from shaking apart? They 00:12:09.960 --> 00:12:12.299 also used rounded corners, which prevent stress 00:12:12.299 --> 00:12:15.360 points from concentrating force. And in the most 00:12:15.360 --> 00:12:17.899 critical structures, they used L -shaped blocks 00:12:17.899 --> 00:12:20.659 to tie outside corners together, essentially 00:12:20.659 --> 00:12:23.659 interlocking the entire structure like a giant 00:12:23.659 --> 00:12:26.720 stone puzzle. Wow. On top of that, you'll notice 00:12:26.720 --> 00:12:29.159 that walls are often offset slightly row to row, 00:12:29.279 --> 00:12:32.190 rather than being perfectly vertical. This subtle 00:12:32.190 --> 00:12:35.129 feature allows for minute movement, minimizing 00:12:35.129 --> 00:12:37.370 the chance of catastrophic collapse during a 00:12:37.370 --> 00:12:40.710 large tremor. It's passive seismic engineering, 00:12:40.909 --> 00:12:43.470 hundreds of years ahead of its time. That addresses 00:12:43.470 --> 00:12:45.769 the lateral forces of earthquakes, but what about 00:12:45.769 --> 00:12:48.710 the vertical forces of water? The area gets massive 00:12:48.710 --> 00:12:51.350 amounts of rainfall, over 1 ,800 millimeters 00:12:51.350 --> 00:12:55.370 or 71 inches per year. That much water on such 00:12:55.370 --> 00:12:57.710 steep slopes should have caused the city to slide 00:12:57.710 --> 00:13:00.450 right off the mountain long ago. How did they 00:13:00.450 --> 00:13:02.809 handle the deluge? The hydraulic engineering 00:13:02.809 --> 00:13:05.250 is, you could argue, even more critical than 00:13:05.250 --> 00:13:07.450 the seismic stability for the sheer longevity 00:13:07.450 --> 00:13:09.970 of the site. They prevented catastrophic erosion 00:13:09.970 --> 00:13:12.669 and mudslides through the extensive use of terraces, 00:13:12.750 --> 00:13:14.909 which are known as endines. Right. And these 00:13:14.909 --> 00:13:16.929 are not just agricultural plots or, you know, 00:13:16.970 --> 00:13:20.330 aesthetic steps. They are crucial works of geotechnical 00:13:20.330 --> 00:13:22.830 stabilization. So they served a dual purpose. 00:13:23.639 --> 00:13:26.139 Farming and slope stabilization. Exactly. The 00:13:26.139 --> 00:13:27.940 hundreds of terraces across the steep slopes 00:13:27.940 --> 00:13:30.419 prevent erosion and secure the foundation of 00:13:30.419 --> 00:13:33.220 the entire settlement. Detailed excavations, 00:13:33.299 --> 00:13:36.019 particularly those led by Kenneth Wright, revealed 00:13:36.019 --> 00:13:37.919 the sheer sophistication of their construction. 00:13:38.120 --> 00:13:40.659 It goes far beyond just simple piles of dirt. 00:13:40.820 --> 00:13:43.559 Each terrace utilized a meticulous layered drainage 00:13:43.559 --> 00:13:45.899 system designed to channel waterway instantly. 00:13:46.279 --> 00:13:48.559 Okay, let's break down those layers. What was 00:13:48.559 --> 00:13:51.769 the recipe for a perfect Inca terrace? Okay, 00:13:51.830 --> 00:13:53.870 so you start at the bottom with a layer of large 00:13:53.870 --> 00:13:57.330 scones. This provides bulk and rapid drainage. 00:13:57.950 --> 00:14:00.809 Then you have a layer of loose gravel, and then 00:14:00.809 --> 00:14:03.049 a mix of sand and gravel, which acts as a filter. 00:14:03.389 --> 00:14:05.509 And on top of that? On top of that, you have 00:14:05.509 --> 00:14:09.210 the rich topsoil at the surface. This layer permeability 00:14:09.210 --> 00:14:12.389 is the key. It ensures water drains rapidly down 00:14:12.389 --> 00:14:14.950 and away, rather than saturating the soil and 00:14:14.950 --> 00:14:17.309 creating the conditions for devastating mudslides 00:14:17.309 --> 00:14:20.200 and slope failure. It was essentially a self 00:14:20.200 --> 00:14:22.620 -draining mountain filter. So even a monsoon 00:14:22.620 --> 00:14:25.100 wouldn't turn the site into a mudslide. Pretty 00:14:25.100 --> 00:14:27.279 much. And that's the definition of sustainable 00:14:27.279 --> 00:14:30.440 engineering. What's incredible is that they engineered 00:14:30.440 --> 00:14:32.700 the stability and then they went a step further 00:14:32.700 --> 00:14:35.279 for the farming aspect. How so? The system was 00:14:35.279 --> 00:14:37.820 so efficient that routine irrigation was generally 00:14:37.820 --> 00:14:39.980 unnecessary because of the high volume of natural 00:14:39.980 --> 00:14:43.820 rain. But here's the logistics nugget. Research 00:14:43.820 --> 00:14:46.220 suggests the rich topsoil found on the terraces 00:14:46.220 --> 00:14:48.259 was likely imported from the Urubamba Valley 00:14:48.259 --> 00:14:50.440 floor. Wait, wait. So they moved a mountain of 00:14:50.440 --> 00:14:53.019 rock to stabilize the slopes, and then they imported 00:14:53.019 --> 00:14:56.139 tons of dirt just to grow crops. That really 00:14:56.139 --> 00:14:58.600 confirms this was a project of, like, unlimited 00:14:58.600 --> 00:15:01.720 imperial budget and political will. Absolutely. 00:15:01.940 --> 00:15:04.559 It wasn't a casual settlement. It was a meticulously 00:15:04.559 --> 00:15:07.299 planned imperial retreat designed to be perfect 00:15:07.299 --> 00:15:10.149 from the geology up. And the same layering techniques, 00:15:10.450 --> 00:15:13.129 slightly modified, were used underneath the main 00:15:13.129 --> 00:15:15.710 city center to protect the structures from flooding 00:15:15.710 --> 00:15:19.190 and instability. The entire urban area was laced 00:15:19.190 --> 00:15:21.990 with canals and water reserves, all for water 00:15:21.990 --> 00:15:24.610 management and erosion control. Despite being 00:15:24.610 --> 00:15:27.129 so geographically isolated, it wasn't disconnected. 00:15:27.330 --> 00:15:29.610 You mentioned earlier the evidence of long -distance 00:15:29.610 --> 00:15:32.009 trade. How do we know they weren't just living 00:15:32.009 --> 00:15:34.590 off their terraces? We know because of artifacts 00:15:34.590 --> 00:15:37.820 that originate far, far away. For example, obsidian 00:15:37.820 --> 00:15:39.779 nodules found at the site have been chemically 00:15:39.779 --> 00:15:42.559 traced back to distant sources, either Titicaca 00:15:42.559 --> 00:15:45.740 or Chivay. This confirms active trade, connecting 00:15:45.740 --> 00:15:48.659 this remote retreat to the extensive pre -Hispanic 00:15:48.659 --> 00:15:50.740 exchange networks. And of course, the principal 00:15:50.740 --> 00:15:52.840 approach to the settlement was always via the 00:15:52.840 --> 00:15:55.679 Inca trail system, the Copacan. Yes, and for 00:15:55.679 --> 00:15:57.919 anyone who might not be familiar, the Copacan 00:15:57.919 --> 00:16:01.559 was this extensive, multi -thousand mile highway 00:16:01.559 --> 00:16:04.129 network built by the Inca. stretching across 00:16:04.129 --> 00:16:06.789 the entire empire, from Ecuador down to Chile 00:16:06.789 --> 00:16:09.809 and Argentina. Machu Picchu was deliberately 00:16:09.809 --> 00:16:12.370 connected to this central artery, especially 00:16:12.370 --> 00:16:15.190 through the monumental Intipunku, the sun gate. 00:16:15.389 --> 00:16:17.629 So it was isolated by altitude but intentionally 00:16:17.629 --> 00:16:20.529 linked by infrastructure. Precisely. Contemporary 00:16:20.529 --> 00:16:22.710 accounts even noted local maintenance of these 00:16:22.710 --> 00:16:25.789 paths, which further complicates that old narrative 00:16:25.789 --> 00:16:28.429 of Machu Picchu being entirely hidden before 00:16:28.429 --> 00:16:31.350 the Spanish conquest. If we connect this engineering 00:16:31.350 --> 00:16:34.190 marvel to the people who inhabited it, the story 00:16:34.190 --> 00:16:36.169 becomes even more interesting. You mentioned 00:16:36.169 --> 00:16:37.990 skeletal studies have kind of shattered the notion 00:16:37.990 --> 00:16:40.570 that this was just a simple, homogenous royal 00:16:40.570 --> 00:16:42.690 retreat for Pachacuti and his family. Completely. 00:16:42.990 --> 00:16:45.509 It was a cosmopolitan hub. So who exactly was 00:16:45.509 --> 00:16:48.240 living and working here? during those 80 years 00:16:48.240 --> 00:16:50.899 of occupation. The estimated permanent population 00:16:50.899 --> 00:16:54.200 was relatively small, around 750 people. Most 00:16:54.200 --> 00:16:56.639 served as permanent support staff, known in Inca 00:16:56.639 --> 00:16:59.299 society as Yanaconas. And these were retainer 00:16:59.299 --> 00:17:01.659 communities. Exactly. They were often taken from 00:17:01.659 --> 00:17:04.519 conquered or allied regions specifically to serve 00:17:04.519 --> 00:17:07.240 the imperial elite. They were essentially skilled, 00:17:07.460 --> 00:17:10.519 non -local labor. And the genetic and forensic 00:17:10.519 --> 00:17:14.099 analysis actually confirms this diversity. Absolutely. 00:17:14.440 --> 00:17:17.160 Genome -wide analyses show they possessed incredibly 00:17:17.160 --> 00:17:20.200 diverse ancestries, including individuals with 00:17:20.200 --> 00:17:24.339 strong Andean, coastal Ecuadorian, and even Amazonian 00:17:24.339 --> 00:17:27.519 lineages. These people lived, reproduced, and 00:17:27.519 --> 00:17:29.759 were buried together, which suggests a diverse, 00:17:29.859 --> 00:17:32.920 integrated support staff for the ruler. brought 00:17:32.920 --> 00:17:34.859 in from all corners of the burgeoning empire. 00:17:35.119 --> 00:17:37.420 It really makes Machu Picchu a microcosm of the 00:17:37.420 --> 00:17:39.380 Inca Empire. That's a great way to put it. It 00:17:39.380 --> 00:17:41.799 was a consolidation of diverse populations serving 00:17:41.799 --> 00:17:44.309 the elite. What specific scientific evidence 00:17:44.309 --> 00:17:46.730 pointed to them being immigrants rather than 00:17:46.730 --> 00:17:49.250 lifelong locals from that valley? Well, there 00:17:49.250 --> 00:17:52.210 are two main lines of evidence. First, chemical 00:17:52.210 --> 00:17:54.750 and isotopic analyses of their bones revealed 00:17:54.750 --> 00:17:57.009 differing levels of trace elements, suggesting 00:17:57.009 --> 00:17:59.369 long -term diets characteristic of specific, 00:17:59.609 --> 00:18:02.309 spaced -apart regions, not just the local high 00:18:02.309 --> 00:18:04.470 -altitude microclimate. Okay, so their bones 00:18:04.470 --> 00:18:06.789 told a story of where they came from. Right. 00:18:07.089 --> 00:18:10.559 And second, Researchers found osteological markers, 00:18:10.819 --> 00:18:13.799 including bone damage caused by water parasites 00:18:13.799 --> 00:18:16.900 that are indigenous to lowland or coastal areas 00:18:16.900 --> 00:18:20.160 of Peru. This confirms they had spent significant 00:18:20.160 --> 00:18:22.799 portions of their lives elsewhere before moving 00:18:22.799 --> 00:18:25.859 to Machu Picchu. And their diets shifted once 00:18:25.859 --> 00:18:28.059 they arrived at the imperial estate, adapting 00:18:28.059 --> 00:18:30.799 to the court's preference. Yes. Their previous 00:18:30.799 --> 00:18:33.380 diets included varying levels of maize, potatoes, 00:18:33.839 --> 00:18:36.400 grains, legumes, and fish, depending on where 00:18:36.400 --> 00:18:39.069 they came from. But the analysis of their short 00:18:39.069 --> 00:18:41.309 -term diet just prior to death, after they had 00:18:41.309 --> 00:18:43.829 moved to Machu Picchu, showed a significant shift 00:18:43.829 --> 00:18:47.250 toward a heavily corn -centric diet. This confirms 00:18:47.250 --> 00:18:49.309 they adapted their food intake to what was likely 00:18:49.309 --> 00:18:52.049 supplied and favored by the Inca elite at the 00:18:52.049 --> 00:18:54.250 retreat. Let's talk about their work. Being support 00:18:54.250 --> 00:18:56.569 staff for royalty sounds easier than hauling 00:18:56.569 --> 00:18:59.190 stones in the Mide system. But what did the archaeology 00:18:59.190 --> 00:19:00.869 actually tell us about their physical health 00:19:00.869 --> 00:19:03.650 and daily labor? The archaeology strongly supports 00:19:03.650 --> 00:19:07.039 the royal support staff theory. Most of the skeletal 00:19:07.039 --> 00:19:09.700 remains found at the site show lower levels of 00:19:09.700 --> 00:19:12.460 degenerative conditions like arthritis and significantly 00:19:12.460 --> 00:19:15.440 fewer severe bone fractures compared to individuals 00:19:15.440 --> 00:19:18.200 found in other parts of the Inca Empire. That's 00:19:18.200 --> 00:19:21.079 a huge contrast. It is. When researchers look 00:19:21.079 --> 00:19:23.420 at Inca individuals who performed heavy physical 00:19:23.420 --> 00:19:26.220 labor, like the forced middle workers or those 00:19:26.220 --> 00:19:28.519 who served in the military, their skeletons show 00:19:28.519 --> 00:19:30.880 massive wear and tear. consistent with years 00:19:30.880 --> 00:19:33.880 of taxing physical stress. But not at Machu Picchu. 00:19:34.019 --> 00:19:36.720 Not really. The residents of Machu Picchu generally 00:19:36.720 --> 00:19:39.940 lived less physically demanding lives, suggesting 00:19:39.940 --> 00:19:42.079 their role was focused on specialized tasks, 00:19:42.359 --> 00:19:45.259 administration, and support services, rather 00:19:45.259 --> 00:19:47.440 than heavy construction or large -scale farming. 00:19:47.700 --> 00:19:50.579 Beyond people, the sources mention animals, including 00:19:50.579 --> 00:19:53.400 those imported for specific purposes. This again 00:19:53.400 --> 00:19:55.500 highlights the incredible logistics involved. 00:19:55.859 --> 00:19:59.200 Indeed. Many animal bones recovered. belonged 00:19:59.200 --> 00:20:02.259 to lanas and alpacas. Now, these camelids naturally 00:20:02.259 --> 00:20:05.359 live at much higher altitudes, closer to 4 ,000 00:20:05.359 --> 00:20:08.259 meters in the Puna region. They were deliberately 00:20:08.259 --> 00:20:11.019 brought down to the 2 ,400 -meter elevation of 00:20:11.019 --> 00:20:13.400 Machu Picchu. And they were essential resources. 00:20:13.759 --> 00:20:16.420 Essential. Imported for meat, transport, and 00:20:16.420 --> 00:20:18.380 their high -quality pilts. And what about the 00:20:18.380 --> 00:20:21.099 ubiquitous guinea pigs? They seem to have served 00:20:21.099 --> 00:20:23.940 a ritual function. Guinea pigs were found in 00:20:23.940 --> 00:20:26.599 special tomb caves, which suggests their use 00:20:26.599 --> 00:20:29.200 in funerary rituals, a common practice across 00:20:29.200 --> 00:20:32.920 the Inca Empire. Interestingly, six dogs were 00:20:32.920 --> 00:20:35.539 also recovered. And their careful placement near 00:20:35.539 --> 00:20:38.319 human remains suggests they were cherished companion 00:20:38.319 --> 00:20:41.180 animals of the dead, which really adds some texture 00:20:41.180 --> 00:20:43.440 to the daily lives of these retainers. Going 00:20:43.440 --> 00:20:45.940 back to agriculture for a moment, we established 00:20:45.940 --> 00:20:48.240 that they imported the topsoil, but they also 00:20:48.240 --> 00:20:51.420 had 750 mouths to feed. How much farming did 00:20:51.420 --> 00:20:53.460 they actually manage on those magnificent terraces? 00:20:53.700 --> 00:20:56.440 The total cultivated terrace farming area only 00:20:56.440 --> 00:20:59.119 accounted for about 4 .9 hectares, or just 12 00:20:59.119 --> 00:21:02.339 acres. That's not a lot. Not at all. While they 00:21:02.339 --> 00:21:05.259 grew staple crops like corn and potatoes, soil 00:21:05.259 --> 00:21:07.819 and yield studies confirmed this amount was fundamentally 00:21:07.819 --> 00:21:11.259 insufficient to support a population of 750 people 00:21:11.259 --> 00:21:14.569 year -round. This is a critical piece of evidence. 00:21:15.049 --> 00:21:17.849 It confirms the suggestion that Machu Picchu 00:21:17.849 --> 00:21:20.859 could not possibly be a self -sustaining Its 00:21:20.859 --> 00:21:23.799 food supply had to be constantly imported. Reliably 00:21:23.799 --> 00:21:26.160 and constantly from surrounding valleys and farther 00:21:26.160 --> 00:21:29.099 afield, reinforcing its profile as a specialized 00:21:29.099 --> 00:21:32.539 seasonal royal retreat entirely dependent on 00:21:32.539 --> 00:21:35.079 the empire's highly efficient logistical network. 00:21:35.359 --> 00:21:37.640 Finally, what about rituals? Was this a place 00:21:37.640 --> 00:21:40.059 of massive human sacrifice like we sometimes 00:21:40.059 --> 00:21:42.880 hear about with other major Inca sites? Well, 00:21:42.880 --> 00:21:45.380 while human sacrifice, specifically the Capacocha 00:21:45.380 --> 00:21:47.799 ritual, which often involved children, was practiced 00:21:47.799 --> 00:21:50.380 at major huacas or sacred places high up in the 00:21:50.380 --> 00:21:52.420 Andes, there is little direct archaeological 00:21:52.420 --> 00:21:54.460 evidence for it at Machu Picchu. Why do you think 00:21:54.460 --> 00:21:56.839 that is? It may be because of its function as 00:21:56.839 --> 00:21:58.519 a retreat rather than a primary administrative 00:21:58.519 --> 00:22:00.759 center. Instead, the evidence points strongly 00:22:00.759 --> 00:22:03.079 toward frequent and extensive animal offerings. 00:22:03.259 --> 00:22:05.640 What kind of animal offerings? primarily camelids, 00:22:05.660 --> 00:22:07.799 llamas, and alpacas. Their remains have been 00:22:07.799 --> 00:22:09.700 documented near the Temple of the Condor and 00:22:09.700 --> 00:22:12.819 adjacent caves, often associated with funerary 00:22:12.819 --> 00:22:15.940 or general ceremonial purposes. The focus here 00:22:15.940 --> 00:22:18.900 seems to have been more on solar rituals, ancestor 00:22:18.900 --> 00:22:21.859 veneration, and agricultural requests, rather 00:22:21.859 --> 00:22:24.180 than those severe imperial Capacocha sacrifices. 00:22:25.069 --> 00:22:27.549 The architecture itself seems to reinforce that 00:22:27.549 --> 00:22:30.130 specialized ceremonial and religious function 00:22:30.130 --> 00:22:32.849 of the site. The urban layout is highly ordered, 00:22:32.970 --> 00:22:35.049 right? It's deliberately split into two halves. 00:22:35.250 --> 00:22:37.730 It is. You have the upper town, Hanan, which 00:22:37.730 --> 00:22:39.769 was dedicated to the religious and ceremonial 00:22:39.769 --> 00:22:42.450 activities, and then the lower town, Hurin, which 00:22:42.450 --> 00:22:44.609 contained residences, doorhouses, and workshops. 00:22:45.150 --> 00:22:47.269 These are all arranged around the main square 00:22:47.269 --> 00:22:49.650 and structured into those trapezoidal compounds 00:22:49.650 --> 00:22:52.190 called conchas. Let's focus on the upper town 00:22:52.190 --> 00:22:54.730 and its most significant structure, the Torion, 00:22:54.829 --> 00:22:57.930 or Temple of the Sun. This semicircular structure 00:22:57.930 --> 00:23:00.289 is built right among these massive, naturally 00:23:00.289 --> 00:23:03.109 occurring granite blocks. The Torion is magnificent. 00:23:03.450 --> 00:23:06.309 It's a direct spiritual echo of the Coricancha, 00:23:06.410 --> 00:23:09.069 the main Temple of the Sun in Cusco, because 00:23:09.069 --> 00:23:11.690 of its parabolic enclosure wall. It's built with 00:23:11.690 --> 00:23:14.410 the site's finest ashlar masonry, which we discussed 00:23:14.410 --> 00:23:17.190 earlier, signifying its immense spiritual importance. 00:23:17.900 --> 00:23:20.339 The base of the structure uses the natural bedrock, 00:23:20.500 --> 00:23:23.380 which is carved with steps and platforms, creating 00:23:23.380 --> 00:23:26.059 a cave -like space sometimes interpreted as the 00:23:26.059 --> 00:23:28.599 Royal Mausoleum. And the upper chamber clearly 00:23:28.599 --> 00:23:31.779 had an astronomical function, but maybe not in 00:23:31.779 --> 00:23:34.000 the way we might imagine a modern observatory. 00:23:34.319 --> 00:23:37.440 Exactly. The upper chamber features a Z -shaped 00:23:37.440 --> 00:23:40.720 altar rock and a distinct system of three openings, 00:23:40.920 --> 00:23:43.740 eastern, southeastern, and northern. Archaea 00:23:43.740 --> 00:23:45.539 astronomical studies have shown that while the 00:23:45.539 --> 00:23:47.819 taurion was not a highly precise astronomical 00:23:47.819 --> 00:23:50.180 instrument for, say, predictive calculations, 00:23:50.619 --> 00:23:52.880 it certainly incorporated solar orientations 00:23:52.880 --> 00:23:55.579 for essential ritual purposes. So it was less 00:23:55.579 --> 00:23:57.680 about science and more about making a spiritual 00:23:57.680 --> 00:23:59.779 connection visible. That's a good way to put 00:23:59.779 --> 00:24:02.039 it. It allows characteristic sunlight patterns 00:24:02.039 --> 00:24:04.420 to fall across the altar rock at key times of 00:24:04.420 --> 00:24:07.519 the year and provides limited framed views of 00:24:07.519 --> 00:24:10.710 important star groups, like the Pleiades. And 00:24:10.710 --> 00:24:12.789 the spiritual connection to the surrounding landscape, 00:24:13.089 --> 00:24:17.789 the sacred mountains or Apis, is vital. A specific 00:24:17.789 --> 00:24:20.089 trapezoidal opening in the Torion, sometimes 00:24:20.089 --> 00:24:22.730 called the serpent's door, leads onto a small 00:24:22.730 --> 00:24:25.349 platform that overlooks a series of pools and 00:24:25.349 --> 00:24:27.789 provides a clear framed view of Huayna Picchu. 00:24:27.950 --> 00:24:30.069 It integrates the celestial with the terrestrial. 00:24:30.349 --> 00:24:32.670 Tying the structure to the peaks that were revered 00:24:32.670 --> 00:24:34.890 as ancestral deities, yes. Speaking of celestial 00:24:34.890 --> 00:24:37.150 connection, let's move to one of the most famous 00:24:37.150 --> 00:24:40.839 sites, the Intuatana Stone. The place where the 00:24:40.839 --> 00:24:43.140 sun is tied. This is one of the features that 00:24:43.140 --> 00:24:45.259 always captures the imagination, but what was 00:24:45.259 --> 00:24:48.519 its actual function? The Intuatana is a uniquely 00:24:48.519 --> 00:24:51.579 carved ritual stone situated on its own terrace 00:24:51.579 --> 00:24:54.420 hill within the Hanan sector, a prominence that 00:24:54.420 --> 00:24:56.299 places it symbolically closer to the heavens. 00:24:56.819 --> 00:24:59.380 While its exact function is still debated, it 00:24:59.380 --> 00:25:01.119 definitely plays a significant role in solar 00:25:01.119 --> 00:25:04.099 alignment. I recall a very specific and surprising 00:25:04.099 --> 00:25:06.740 detail about its alignment and shadows. Yes. 00:25:07.059 --> 00:25:09.480 This is a brilliant piece of engineering observation 00:25:09.480 --> 00:25:12.559 based on the site's latitude, which is 13 degrees 00:25:12.559 --> 00:25:14.920 south of the equator. Because of this location, 00:25:15.160 --> 00:25:18.279 at midday on two specific dates, November 11 00:25:18.279 --> 00:25:21.880 and January 30, the sun is situated almost exactly 00:25:21.880 --> 00:25:24.380 above the pillar. Causing it to cast no shadow. 00:25:24.700 --> 00:25:27.369 Exactly. It cast no shadow. And that alignment 00:25:27.369 --> 00:25:29.670 would have been incredibly important for ceremonial 00:25:29.670 --> 00:25:32.509 observations marking specific calendrical points. 00:25:32.650 --> 00:25:34.890 It allowed them to fix the time of the sun's 00:25:34.890 --> 00:25:38.069 passage through the zenith. It did. But it's 00:25:38.069 --> 00:25:40.069 crucial to note that scholars generally reject 00:25:40.069 --> 00:25:42.390 the popular idea that it was a simple solar calendar 00:25:42.390 --> 00:25:45.509 nomad for basic daily timekeeping. Its primary 00:25:45.509 --> 00:25:47.849 purpose was far deeper likely for horizontal 00:25:47.849 --> 00:25:50.910 solar observations and holding profound symbolic 00:25:50.910 --> 00:25:53.690 significance, visually aligning with sacred peaks 00:25:53.690 --> 00:25:56.789 like Veronica, Salcante, and Huayna Picchu. So 00:25:56.789 --> 00:25:59.349 if the Torreon focuses on the Pleiades and general 00:25:59.349 --> 00:26:02.650 solar ritual and the Inti Potana focuses on shadowless 00:26:02.650 --> 00:26:05.869 days, where do we find the most precise solar 00:26:05.869 --> 00:26:09.250 observatory? That brings us to Inti Maché, or 00:26:09.250 --> 00:26:12.190 the Sun Cave, a specialized structure located 00:26:12.190 --> 00:26:15.849 on the eastern side of Machu Picchu. Architecturally, 00:26:16.009 --> 00:26:18.809 this structure contains some of the finest masonry 00:26:18.809 --> 00:26:21.910 found in the entire Inca Empire. The precision 00:26:21.910 --> 00:26:24.710 of the stonework here is exceptional, even by 00:26:24.710 --> 00:26:27.430 Inca standards. What makes its windows so specialized? 00:26:27.849 --> 00:26:30.650 That unique, tunnel -like window is engineered 00:26:30.650 --> 00:26:33.609 so that sunlight enters the cave interior only 00:26:33.609 --> 00:26:36.049 for a few days around the December solstice. 00:26:36.089 --> 00:26:37.990 Which is when the sun reaches its lowest arc 00:26:37.990 --> 00:26:40.480 in the southern hemisphere. Right. This precise 00:26:40.480 --> 00:26:43.359 alignment suggests it functioned explicitly as 00:26:43.359 --> 00:26:46.319 a solar observatory linked to the Capac Rami, 00:26:46.460 --> 00:26:49.039 or the Royal Feast of the Sun. This sounds like 00:26:49.039 --> 00:26:51.380 a festival of major social and political importance. 00:26:51.539 --> 00:26:54.359 It was crucial. The Capac Rami was a critical 00:26:54.359 --> 00:26:56.799 festival where noble boys were initiated into 00:26:56.799 --> 00:26:59.960 manhood through an ear -piercing ritual. Historical 00:26:59.960 --> 00:27:02.460 sources suggest the ritual involved the initiates 00:27:02.460 --> 00:27:05.019 watching the sunrise from inside the cave, marking 00:27:05.019 --> 00:27:06.940 their transition as the sun aligned perfectly 00:27:06.940 --> 00:27:09.190 with the structure. Wow, that underscores the 00:27:09.190 --> 00:27:11.430 ceremonial gravity of this particular structure. 00:27:11.670 --> 00:27:14.569 And the political elite who inhabited Machu Picchu 00:27:14.569 --> 00:27:16.809 seasonally. Before we leave the sacred plaza, 00:27:16.890 --> 00:27:18.789 let's quickly touch on the Temple of the Three 00:27:18.789 --> 00:27:22.089 Windows. It sounds deceptively simple. but it's 00:27:22.089 --> 00:27:24.930 architecturally complex. It stands prominently 00:27:24.930 --> 00:27:27.410 on the Sacred Plaza and features this magnificent 00:27:27.410 --> 00:27:31.589 trapezoidal wall made of large, finely worked 00:27:31.589 --> 00:27:35.670 white granite blocks. It's defined by three oversized 00:27:35.670 --> 00:27:38.990 trapezoidal openings flanked by two smaller niches. 00:27:39.269 --> 00:27:41.750 Evidence suggests it was originally roofed by 00:27:41.750 --> 00:27:44.450 a three -wall timber truss system designed to 00:27:44.450 --> 00:27:46.849 let occupants observe both sunrise and sunset. 00:27:47.240 --> 00:27:49.839 And this building actually holds a piece of modern, 00:27:49.940 --> 00:27:52.460 if controversial, history that connects directly 00:27:52.460 --> 00:27:55.099 to the rediscovery narrative. It does. It's notable 00:27:55.099 --> 00:27:57.299 because this is precisely where the Peruvian 00:27:57.299 --> 00:28:00.640 explorer Agustin Lizarga left his charcoal inscription 00:28:00.640 --> 00:28:04.650 in 1902, years before Bingham arrived. That graffiti, 00:28:04.849 --> 00:28:07.809 La Zarga in 1902, was clearly visible when Bingham 00:28:07.809 --> 00:28:09.990 first photographed the site. It's a physical 00:28:09.990 --> 00:28:12.470 testament to the local knowledge and prior visitation 00:28:12.470 --> 00:28:15.150 that Bingham later minimized in his popular accounts. 00:28:15.390 --> 00:28:17.650 The history of Machu Picchu's introduction to 00:28:17.650 --> 00:28:20.970 the global stage is often simplified into Hiram 00:28:20.970 --> 00:28:24.569 Bingham discovered the lost city in 1911. But 00:28:24.569 --> 00:28:26.769 as we've established, the sources tell a much 00:28:26.769 --> 00:28:29.490 messier, more complex story, especially when 00:28:29.490 --> 00:28:31.569 it comes to who deserves credit. Right. And it 00:28:31.569 --> 00:28:35.240 forces us to ask. What defines discovery? Bingham, 00:28:35.339 --> 00:28:37.799 who was a Yale lecturer but not a trained archaeologist, 00:28:37.980 --> 00:28:41.039 arrived in 1911 searching for a completely different 00:28:41.039 --> 00:28:44.319 place, the lost Neo -Inca capital of Vitkos. 00:28:44.420 --> 00:28:46.299 Which was later correctly identified elsewhere. 00:28:46.420 --> 00:28:49.460 Correct. He was led to Machu Picchu not by academic 00:28:49.460 --> 00:28:51.920 deduction, but by local indigenous knowledge. 00:28:52.460 --> 00:28:54.660 He was searching along the Urubamba River, armed 00:28:54.660 --> 00:28:57.079 with some general historical references. What 00:28:57.079 --> 00:28:59.359 specific guidance did he receive? Well, at a 00:28:59.359 --> 00:29:01.839 place called Mandopampa, he asked Melkor Arteaga, 00:29:02.019 --> 00:29:04.200 a local farmer, who said he knew of excellent 00:29:04.200 --> 00:29:07.000 ruins atop Huayna Picchu. The next day, July 00:29:07.000 --> 00:29:11.119 24, 1911, Arteaga led Bingham up. They found 00:29:11.119 --> 00:29:13.779 a small hut occupied by a Quechua couple, Rucharte 00:29:13.779 --> 00:29:16.559 and Alvarez, who were actively farming the cleared 00:29:16.559 --> 00:29:18.680 Inca terraces. So it wasn't exactly abandoned. 00:29:19.160 --> 00:29:21.920 Not at all. And it was Ricard's 11 -year -old 00:29:21.920 --> 00:29:24.960 son, Pablito, who actually led Bingham along 00:29:24.960 --> 00:29:27.839 the ridge to the main ruins. So he was guided 00:29:27.839 --> 00:29:30.440 to a site that was actively being farmed by local 00:29:30.440 --> 00:29:32.819 families who were well aware of its existence. 00:29:33.140 --> 00:29:35.799 That's already a huge blow to the whole lost 00:29:35.799 --> 00:29:38.700 city narrative. And that's compounded by the 00:29:38.700 --> 00:29:41.579 previous visitation we just discussed. Agustin 00:29:41.579 --> 00:29:45.039 Lazarega had visited in 1902 and left his inscription. 00:29:45.529 --> 00:29:48.589 In Bingham's own pocket field journal, he initially 00:29:48.589 --> 00:29:52.630 noted, Augustin Lizarga is discoverer of Machu 00:29:52.630 --> 00:29:55.490 Picchu. He wrote that down himself. He did. The 00:29:55.490 --> 00:29:57.750 initial documentation clearly acknowledged the 00:29:57.750 --> 00:30:00.529 local and previous Peruvian exploration. But 00:30:00.529 --> 00:30:03.240 the narrative changed over time, didn't it? Bingham's 00:30:03.240 --> 00:30:05.619 later writings downplayed Lazarega and the local 00:30:05.619 --> 00:30:08.099 farmers. Significantly. While Bingham initially 00:30:08.099 --> 00:30:10.160 acknowledged Lazarega in his early writings, 00:30:10.279 --> 00:30:13.720 like Inca Land in 1922, he gradually minimized 00:30:13.720 --> 00:30:15.799 his role, focusing instead on the scientific 00:30:15.799 --> 00:30:18.619 importance of his own documentation. By his final, 00:30:18.740 --> 00:30:21.680 famous version, Lost City of the Incas in 1952, 00:30:21.940 --> 00:30:24.859 he had adopted the position that he was the scientific 00:30:24.859 --> 00:30:27.640 discoverer. Claiming it was so overgrown he couldn't 00:30:27.640 --> 00:30:30.509 even see it at first. Exactly. He essentially 00:30:30.509 --> 00:30:33.289 argued that his expedition, sponsored by Yale 00:30:33.289 --> 00:30:35.650 and National Geographic, was the one that brought 00:30:35.650 --> 00:30:38.029 the ruins to international scientific attention, 00:30:38.390 --> 00:30:41.400 making him the rightful discoverer. in a global 00:30:41.400 --> 00:30:44.000 sense. The controversy didn't stop with the name 00:30:44.000 --> 00:30:46.359 and the credit. It escalated dramatically when 00:30:46.359 --> 00:30:49.119 Bingham started his full -scale excavations between 00:30:49.119 --> 00:30:53.380 1912 and 1915. He removed thousands of items, 00:30:53.619 --> 00:30:57.000 knives, jewelry, human bones, shipping them to 00:30:57.000 --> 00:30:59.900 Yale under the guise of an 18 -month study period. 00:31:00.160 --> 00:31:02.980 That sounds suspiciously convenient for Yale. 00:31:03.279 --> 00:31:05.880 It was a complex legal gray area, but you have 00:31:05.880 --> 00:31:07.980 to remember the context. Bingham was operating 00:31:07.980 --> 00:31:11.390 under the 1852 Civil Code of Peru. And that law 00:31:11.390 --> 00:31:13.529 stated that the discoverer of antiquities not 00:31:13.529 --> 00:31:15.910 on private land was entitled to a share of the 00:31:15.910 --> 00:31:17.930 fines. So he was technically adhering to that. 00:31:18.150 --> 00:31:20.529 Technically. Yeah. He signed agreements to take 00:31:20.529 --> 00:31:22.529 the artifacts for an 18 -month study period. 00:31:22.789 --> 00:31:25.509 So he wasn't technically smuggling, but he was 00:31:25.509 --> 00:31:27.569 exploiting a system that favored the Western 00:31:27.569 --> 00:31:30.009 discoverer and using the lack of infrastructure 00:31:30.009 --> 00:31:33.230 in Peru as justification to keep the items indefinitely. 00:31:33.690 --> 00:31:36.289 Exactly. That 18 -month study period stretched 00:31:36.289 --> 00:31:39.200 for nearly a century. Yale kept the artifacts, 00:31:39.500 --> 00:31:42.420 citing Carew's lack of infrastructure, and the 00:31:42.420 --> 00:31:45.140 removal included thousands of items, ceramic 00:31:45.140 --> 00:31:48.740 vessels, silver statues, jewelry, human bones, 00:31:48.900 --> 00:31:52.160 and a set of 15th century ceremonial knives made 00:31:52.160 --> 00:31:54.819 from bismuth bronze, which are historically significant 00:31:54.819 --> 00:31:57.099 as the earliest known artifacts with this specific 00:31:57.099 --> 00:32:00.579 alloy. This provoked an intense local and cultural 00:32:00.579 --> 00:32:04.000 fight in Peru, accusing Bingham of cultural malpractice 00:32:04.000 --> 00:32:05.960 despite his adherence to the letter of the old 00:32:05.960 --> 00:32:08.299 law. How long did it take for those protests 00:32:08.299 --> 00:32:10.779 to really gain international traction? It took 00:32:10.779 --> 00:32:14.079 decades. Local coalitions formed almost immediately, 00:32:14.339 --> 00:32:17.000 but the dispute gained major international esteem 00:32:17.000 --> 00:32:19.690 in the early 2000s. The Peruvian government launched 00:32:19.690 --> 00:32:21.970 legal battles, demanding the return of all materials. 00:32:22.269 --> 00:32:24.589 The pressure became intense, evolving from a 00:32:24.589 --> 00:32:26.490 simple legal claim into a major international 00:32:26.490 --> 00:32:29.049 cultural heritage fight. And the matter was resolved 00:32:29.049 --> 00:32:31.289 officially only about a decade ago. Correct. 00:32:31.630 --> 00:32:34.930 After years of intense legal and cultural pressure, 00:32:35.369 --> 00:32:38.130 Yale finally acknowledged Peru's clear title 00:32:38.130 --> 00:32:41.630 to all the objects in 2007. The agreement stipulated 00:32:41.630 --> 00:32:43.690 Yale would share rights only in the research 00:32:43.690 --> 00:32:45.690 collection, part of which would remain there 00:32:45.690 --> 00:32:47.980 for continuing study. And the final batch was 00:32:47.980 --> 00:32:50.420 returned when? The final batch of thousands of 00:32:50.420 --> 00:32:53.700 artifacts was delivered in November 2012. They 00:32:53.700 --> 00:32:55.940 are now permanently exhibited at the Machu Picchu 00:32:55.940 --> 00:32:59.059 Museum Casa Concha in Cusco, securing them within 00:32:59.059 --> 00:33:01.200 their cultural homeland. Fast forward to today, 00:33:01.460 --> 00:33:03.819 the challenge isn't rediscovery or ownership, 00:33:04.000 --> 00:33:06.259 it's preservation against overwhelming popularity. 00:33:06.779 --> 00:33:09.339 What's the scale of modern tourism pressure and 00:33:09.339 --> 00:33:11.640 how is it impacting the site? The pressure is 00:33:11.640 --> 00:33:14.230 immense. Machu Picchu is Peru's most visited 00:33:14.230 --> 00:33:16.730 international destination. We're talking well 00:33:16.730 --> 00:33:20.190 over 1 .5 million visitors annually as of 2024. 00:33:20.670 --> 00:33:23.329 This scale exposes the site to severe economic 00:33:23.329 --> 00:33:25.609 and commercial pressures, forcing incredibly 00:33:25.609 --> 00:33:27.450 difficult decisions about visitor management. 00:33:27.789 --> 00:33:30.150 I know UNESCO has voiced concerns about overcrowding, 00:33:30.210 --> 00:33:32.450 specifically citing potential erosion and damage 00:33:32.450 --> 00:33:34.390 to the stonework from just the sheer volume of 00:33:34.390 --> 00:33:36.990 foot traffic. What have authorities done to manage 00:33:36.990 --> 00:33:39.509 that flow? Streaker entrance regulations began 00:33:39.509 --> 00:33:42.400 in 2011. originally limiting daily visitors to 00:33:42.400 --> 00:33:46.099 2 ,500. But the economic reality often outweighs 00:33:46.099 --> 00:33:49.059 conservation concerns. Due to substantial lobbying, 00:33:49.440 --> 00:33:52.220 that limit was significantly increased in 2024 00:33:52.220 --> 00:33:56.079 to 4 ,500 daily, with up to 4 ,600 permitted 00:33:56.079 --> 00:33:58.940 during peak seasons. And that's despite UNESCO's 00:33:58.940 --> 00:34:01.440 concerns. Yes, despite previous concerns from 00:34:01.440 --> 00:34:03.980 UNESCO that considered including the site on 00:34:03.980 --> 00:34:06.539 its list of World Heritage in Danger. It's a 00:34:06.539 --> 00:34:08.420 continuous balancing act between preservation 00:34:08.420 --> 00:34:11.519 and economic necessity. And the sources mentioned 00:34:11.519 --> 00:34:14.059 significant conflicts over infrastructure projects 00:34:14.059 --> 00:34:16.440 near the site, often related to accommodating 00:34:16.440 --> 00:34:19.099 that huge influx of people. Yes. There have been 00:34:19.099 --> 00:34:21.440 numerous controversies. In the late 1990s and 00:34:21.440 --> 00:34:23.679 again more recently, controversial plans for 00:34:23.679 --> 00:34:26.159 cable cars, bridges, and luxury hotels have faced 00:34:26.159 --> 00:34:28.699 widespread protests. Critics argued the government 00:34:28.699 --> 00:34:30.519 failed to conduct proper environmental impact 00:34:30.519 --> 00:34:33.199 surveys, threatening the fragile ecosystem. And 00:34:33.199 --> 00:34:35.219 that opposition was strong enough to create a 00:34:35.219 --> 00:34:37.760 no -fly zone. It was. A no -fly zone currently 00:34:37.760 --> 00:34:39.920 exists above the area to protect the site from... 00:34:39.949 --> 00:34:44.090 For travelers, accessing the site is complex. 00:34:44.469 --> 00:34:46.829 What are the main physical routes? There are 00:34:46.829 --> 00:34:50.349 three primary ways. First, the majority take 00:34:50.349 --> 00:34:53.550 the scenic train from Cusco or Olante Tambo to 00:34:53.550 --> 00:34:57.190 Aguas Calientes, the town below the ruins, and 00:34:57.190 --> 00:34:59.409 then take a regulated bus up the mountain. Then 00:34:59.409 --> 00:35:02.010 there's the Inca Trail. Right. The highly regulated 00:35:02.010 --> 00:35:05.170 multi -day Inca Trail system that spans about 00:35:05.170 --> 00:35:08.630 42 .5 kilometers and requires limited permits 00:35:08.630 --> 00:35:10.769 and advanced booking because of the high environmental 00:35:10.769 --> 00:35:12.869 impact of the trekking route. And the third, 00:35:12.929 --> 00:35:15.409 more unconventional route. That's the hydroelectric 00:35:15.409 --> 00:35:18.150 route. It involves traveling by road closer to 00:35:18.150 --> 00:35:20.449 the hydroelectric station and then walking or 00:35:20.449 --> 00:35:22.969 taking a short train to Aguas Calientes. It's 00:35:22.969 --> 00:35:24.769 more affordable but carries higher risks during 00:35:24.769 --> 00:35:28.130 the rainy season. And notably, the Peruvian government 00:35:28.130 --> 00:35:30.469 is pursuing infrastructure improvements. There's 00:35:30.469 --> 00:35:32.909 a paved highway under construction planned for 00:35:32.909 --> 00:35:35.989 completion in 2025. Which will make access easier, 00:35:36.130 --> 00:35:38.469 but probably increase traffic. That's the fear 00:35:38.469 --> 00:35:40.590 among conservationists, yes. Finally, we should 00:35:40.590 --> 00:35:43.190 note the site's designation as a sanctuary because 00:35:43.190 --> 00:35:45.769 it involves more than just the stones. The whole 00:35:45.769 --> 00:35:48.989 ecosystem is protected. Absolutely. In 1981, 00:35:49.329 --> 00:35:53.150 Peru declared a vast area of 325 square kilometers 00:35:53.150 --> 00:35:56.199 around Machu Picchu a historic sanctuary. This 00:35:56.199 --> 00:35:57.880 protects not just the architecture, but also 00:35:57.880 --> 00:36:00.579 the vast biodiversity of the Peruvian Yungas 00:36:00.579 --> 00:36:04.480 and central Andean wet Puna ecoregions. The sanctuary 00:36:04.480 --> 00:36:07.739 is home to over 550 tree species, as well as 00:36:07.739 --> 00:36:10.099 fauna like the Andean condor, the puma, and the 00:36:10.099 --> 00:36:12.659 spectacled bear. It's a conservation area of 00:36:12.659 --> 00:36:15.019 global importance. So what does this deep dive 00:36:15.019 --> 00:36:17.579 truly reveal about Machu Picchu? The deepest 00:36:17.579 --> 00:36:19.659 insight is that it was far from an isolated, 00:36:19.820 --> 00:36:22.679 lost city stumbled upon by a foreigner. It was 00:36:22.679 --> 00:36:24.940 a strategically chosen, geologically informed, 00:36:25.179 --> 00:36:27.880 short -lived royal estate. It dates slightly 00:36:27.880 --> 00:36:30.280 earlier than we previously thought and was populated 00:36:30.280 --> 00:36:32.920 by a highly diverse cosmopolitan retainer class 00:36:32.920 --> 00:36:35.460 brought in from across the Inca Empire. And its 00:36:35.460 --> 00:36:37.739 original identity, possibly Huayna Picchu, was 00:36:37.739 --> 00:36:39.699 unfortunately overwritten by the narrative of 00:36:39.699 --> 00:36:41.920 its modern rediscovery. But its true genius lies 00:36:41.920 --> 00:36:44.150 in its construction. It's a remarkable story 00:36:44.150 --> 00:36:47.150 of human mastery over nature. We learned that 00:36:47.150 --> 00:36:49.489 the Inca intentionally located their city on 00:36:49.489 --> 00:36:52.489 major fault lines, not out of foolishness, but 00:36:52.489 --> 00:36:55.329 to gain easier access to materials, turning a 00:36:55.329 --> 00:36:57.889 geological weakness into a massive logistical 00:36:57.889 --> 00:36:59.869 strength. And then they stabilized the whole 00:36:59.869 --> 00:37:03.190 structure using unparalleled dry masonry techniques, 00:37:03.570 --> 00:37:06.650 trapezoidal shapes to resist sheer forces, and 00:37:06.650 --> 00:37:09.329 those elaborate multi -layered hydraulic systems 00:37:09.329 --> 00:37:11.309 that prevented the mountain from washing away. 00:37:12.030 --> 00:37:14.650 The lessons in adaptive, sustainable engineering 00:37:14.650 --> 00:37:17.230 and water management are profound, particularly 00:37:17.230 --> 00:37:19.690 given the challenges we face today in volatile 00:37:19.690 --> 00:37:22.190 environments. Which leaves us with this provocative 00:37:22.190 --> 00:37:24.960 thought for you to mull over. Given that the 00:37:24.960 --> 00:37:27.340 Inca intentionally located their city on fault 00:37:27.340 --> 00:37:29.820 lines for building stability and material accessibility, 00:37:30.139 --> 00:37:33.059 exploiting what we would call a risk, what assumptions 00:37:33.059 --> 00:37:35.500 might we still be making about lost ancient cities? 00:37:35.579 --> 00:37:37.460 And what essential lessons about sustainable 00:37:37.460 --> 00:37:40.320 adaptive engineering might remain buried beneath 00:37:40.320 --> 00:37:42.820 the moss and topsoil? Think about the genius 00:37:42.820 --> 00:37:45.019 required to solve problems that way, you know, 00:37:45.019 --> 00:37:47.139 using the land instead of fighting it. Thank 00:37:47.139 --> 00:37:49.420 you for joining us on this deep dive. We'll see 00:37:49.420 --> 00:37:49.960 you next time.