I have just looked at a lot of structures from space using Google Earth, including just about every Pyramid. It is an obsessive hobby and addiction. I have been let down many times like this in my “treasure hunts”.
I really get disillusioned when I see photographs of ancient sites that were taken at angles that make them look like they are in a cool remote isolated location. Then I jump on Earth and go look at it only to find out it is DOWNTOWN in the middle of a huge city with several tourist hotels next to it. Yep, Just camera angles. lol
But in turn, I have found a lot of very cool stuff too. :)
Then it has been worth it. :)
Here is a site which covers more than 300 miles square, and may have taken thousands of years to build, but because it is in Africa, we don’t know about it. So far as I know, National Geographic has never sponsored any major research on it. I have spent hours on Google Earth going all over this huge area, and from erosion and sand coverage my guess is that it covers thousands of years of development at various times. I wonder if the civilization at Greater Zimbabwe was created by the people who used to live at those channels. There are several other links with other photos, but looking down on them yourself is the most revealing.
http://earthepochs.blogspot.com/2014/04/the-largest-man-made-system-on-earth.html