8 Armed Visnu Statue at Angkor
Angkor InformationThe original Angkor Archaeological Park was 300 sq km, but the cultural heritage region is 5000 sq km (1930 sq mi)--of which over 1000 sq km, from the Tonle Sap to the Kulen Hills, was the urban complex (according to the University of Sydney); this would make Angkor the most extensive pre-industrial city in the world. This expansive city's location was not settled for any religious or cultural significance, but rather for its agricultural potential, as it sits on a large basin framed by the Great Lake (Tonle Sap) and the Kulen hills while being drained by tributaries of Siem Reap River.
The Khmer constructed a series of large reservoirs and dikes, most notably the East Baray (holding 55 million cubic meters of water) and the West Baray (holding over 123 million cubic meters of water), and from these and the Great Lake, Angkor was able to survive by collecting water from rivers for agriculture as well as draining and reserving water from the monsoon season. Storing the water helped as the area only had two seasons: dry and rainy. Thus, during the rainy season, water would be collected to prevent flooding and to provide irrigation for crops during the dry season.