We Solved The Mystery Of The Pyramids

As one of the seven wonders of the world, the Great Pyramid of Giza has fascinated people for a long time, probably pretty much since it was built. And in that time, we've learned a lot about it and other pyramids around Giza. We know that they were constructed between roughly 2575 and 2465 BCE, and we know they were built to be tombs and temples. But one thing we didn't know is why they were built where they are, because these things are in the middle of the desert, kilometers away from where we'd expect them, along the Nile River. After centuries of studies, though, we may have finally solved that mystery. And it turns out, the answer may have been hiding just below ground the whole time. So to start off, the Giza Pyramid Complex is actually way more than just the Great Pyramid. There are also two other main pyramids, plus the Sphinx, plus several smaller pyramids and temples. The whole complex was built about 7 kilometers west of the Nile and about 10 kilometers from Bennifer, the capital of Egypt at that time. So pretty much out of the way when you don't have a dune buggy to get around on. And the tools and materials used to build the pyramids came from all over, including copper from the Sinai Peninsula, timber from Lebanon, and granite for the exterior from the city of Aswan, up the river. Papyri from the Sinai Peninsula tell us that Egyptians used barges to transport these heavy building materials down the Nile, and then possibly created artificial waterways to get the supplies from the Nile to the pyramid site. But that would still mean making over 7 kilometers of waterway, so the question remains why they picked that exact site in the first place. Like, instead of building canals leading to an artificial lake, it would have been a lot easier to just… pick somewhere closer to the Nile. Well, it turns out that they were a lot closer to running water than we thought. Using radar satellites, researchers have been able to get a picture of what was under the surface of the desert. And they were able to see these tiny little depressions, which were covered up by nearby farmland, which is why they'd been so hard to spot before. When the researchers took samples of the earth from more than a dozen meters below the surface, they found sand at the bottom. And yeah, that doesn't sound like a very big deal, like of course there's sand, it's a desert. But sand is normally only the top layer of a desert environment, and so when you find it lower down, that usually indicates that there used to be running water there. Putting together the channels they saw on the satellite imagery with the discovery of sand beneath the surface led the researchers to conclude that thousands of years ago, a branch of the Nile flowed through the area, parallel to the main river, but several kilometers to the west. They're calling this now-dried-up branch the Aramut branch, which is Arabic for pyramid branch. Which is pretty fitting, since aside from Giza, there are 31 pyramids located along the 64-kilometer stretch of the former river that they were able to track. Thanks to Arizona State University's College of Global Futures for supporting this SciShow video. It's the academic home for students looking to foster a thriving, healthy planet for everyone, because people around the world don't have the same access to wealth and resources. So at ASU, they ask how we can bridge deep global inequalities, what role technology will play in meeting everyone's needs, how it can be used to ensure greater good, and other meaningful questions aimed to create a more just and equitable future for all. And when you take their master's program in Global Technology and Development, you can address these questions by exploring history, social science, government policies, and development projects from around the world. This program in International Development examines social, economic, and political development by combining technology and global studies. In the end, you'll be prepared to start a job in foreign service, social and environmental justice groups, or a federal agency. Once you've experienced ASU's programs at the College of Global Futures, you can align your careers with purpose. The pyramids on the Aramut branch were built over the 1000-year period between 2600 and 1600 BCE, suggesting that this was a significant Egyptian waterway for quite a while. But now, just a few thousand years later, there's barely a trace of the Aramut branch left. So what happened to it? It's likely that the disappearance of the Aramut is related to larger changes in the Nile River Valley over the last 14,000 years. Back then, the eastern Sahara Desert was a lot wetter than it is today, thanks to stuff like glacial melt and sea level rise. There were large river systems and lakes, and the amount of rainfall actually made it a savanna or grassland instead of a desert. It's even known as the African Human Period. At that time, there was so much water that the Nile River Valley was a soupy, swampy mess that meant it was pretty much inhospitable, which meant that there was enough water that the Nile River would have easily formed other branches, and nobody could actually live anywhere near the actual rivers because there was too much swamp in the way. Somewhere between 6 and 10,000 years ago, things started to dry out enough to allow people to live a little closer to the riverbanks. And then about 5,000 years ago, things shifted even more dramatically. Less rainfall allowed the sediment to build up in the Nile floodplain, which meant there was a whole bunch of dry farmland above the marshes. And the new dryness of the Sahara pushed settlements even closer toward the Nile, where there was still water. But things were still wetter than they are now, allowing for those branches of the Nile to keep thriving. Branches like the Aramat. When and where settlements were built tells us what was happening with the location and water level of the Aramat over time. And tracking those settlements showed that the river started to dry up, but also slowly shifted more towards the east. This change was likely due to a few factors, including a shift in tectonic plates that tilted the ground so the Aramat was basically uphill from the main stretch of the Nile. And then that tilt, combined with windblown sand and sediment building up along the river, caused the Aramat to finally run dry. And just like that, the river was hidden for millennia. Uncovering the Aramat is the first step in discovering more hidden aspects of ancient Egypt. Because we know that people like to build settlements along rivers, researchers think that following the branch's path will allow archaeologists to discover new sites and better preserve them. It also provides new information on the cultural development and interconnectivity and trade routes of ancient Egypt, because it means that many cities and towns were directly connected by river, not just over land. Which just goes to show that even after thousands of years, there's still so much more to learn about the pyramids. Who knows what other secrets are buried in the sands of the Sahara?