The city of Angkor was once the seat of the Khmer Empire in Southeast Asia. Starting about the year 802, Angkor flourished. But by 1430, the city was mysteriously abandoned, then swallowed up by jungle. Now, cutting-edge technology is revealing what likely led to Angkor’s collapse. Sarah Klassen is an archaeologist at the University of Colorado in Boulder, and one of the researchers featured in the new PBS NOVA documentary. Klassen recently spoke to Host Marco Werman.