The Inca Road was built by engineers and laborers working with bronze and stone tools and llamas. At the height of the Inca Empire, it integrated nearly ten million people from a hundred nations.

The Silk Road, a vast web of interconnected trade paths ... These cities were part of the vast empire ruled by the Karakhanids, a powerful Turkic dynasty that controlled much of Central Asia.

"A thousand years ago we were once part of the magnificent Inca Empire, which also suffered climate change. They planted millions of trees to manage the weather," says Cusco-based Aucca.