Angkor was the site of several capital pf the Khmer Empire, north of Tõnlê Sap lake, in northwest Cambodia. For about five and half centuries (9th to 15th), it was the heart of the empire. Extending over an area of 120 sq mi (323 sq km), the ruins contains some of the most imposing monuments in the world, including about a thousand temples, mainly Hindu and some Buddhist, the ancient city, however, had an extent perhaps nearly 10 times that size (according to satellite photographs published in 2007), and was home to perhaps 750,000 people.