Located on the northern edge of the Tonlé Sap lake, the ancient city of Angkor was once the vibrant capital of the Khmer Empire. Flourishing from the 9th to 15th centuries, it was largest pre-industrial city in the world with an estimated population of up to a million. The landscape is filled with more than 1,000 Hindu and Buddhists temples, including Angkor Wat — the world’s largest single religious monument.