Illustration showing the floor plan of Angkor, site of the ancient capital of the Khmer Empire in Cambodia. At centre is the walled city Angkor Thom. At the centre of the city is the Bayon, the state temple. The smaller area at bottom right is the temple of Angkor Wat. Angkor Thom was one of the largest cities in the world from the 9th to the 12th century. The area was excavated by the French in the 1860s.