1000 years ago, the Khmer people in Cambodia built a kingdom that stretched a million square kilometers. Its capital was the lost jungle city of Angkor, once the largest on Earth. The lives of the people who lived there largely remains a mystery. But now an innovative scientific project is shedding new light on this metropolis. It might also reveal the reasons for Angkor's mysterious collapse.

Deep in the Cambodian jungle, scientists using cutting edge technology have unearthed a lost city's sophisticated network of roads and canals. As this gripping history documentary reveals, this is the forgotten world of Angkor's greatest king, a leader still revered today. Unlocking the secrets of how the vast city flourished could reveal why this medieval metropolis was abandoned to the jungle.