Only quite recently (2007) did we discover that the Angkor Wat site was the epicentre of a large Cambodian society. This was found through the use of NASA equipment, specifically designed for ground sensing.
There is also speculation that war impacted the city more than the increasing population. Thailand's invasion of the Cambodian Empire, may have impacted the state and livability of the land and society.
Scientists still have many questions about this site, however the Angkor Wat is nowadays mainly enjoyed by tourists. This threatens the area for further research, as the visitors impact the state of the land. The excessive use of water is threatening the water table of the land, and the stones are being worn from traffic.