Hidden deep within the jungles of Cambodia stands Angkor Wat, the largest religious structure ever built and one of the greatest engineering achievements of the ancient world. Constructed during the height of the Khmer Empire in the 12th century, this vast temple complex covers more than 160 hectares and was completed in just a few decades. But how was such an enormous monument built in the middle of the jungle, and what secrets still remain hidden beneath the landscape surrounding it?