The Astounding Incan Moray Circles, Peru
These huge concentric circular terraces (look for the people!) are a testament to ancient engineering. Each massive terrace hewn into the hillside emulates an agricultural altitude zone which allowed the Incas to grows crops that would have otherwise been impossible. The temperature difference between the top and bottom terrace can be as much as 15 degrees. Water channels ensured equal rainfall for each level and a perfect drainage system ensured that not even the bottom layer would flood.