Cambodia contains Angkor, the world's largest archaeological site by area.
Angkor was the centre of the Khmer Empire from the ninth to the fifteenth centuries. It lies in northwestern Cambodia near the modern city of Siem Reap. The site includes temples, reservoirs, roads, canals and urban settlements spread across more than 400 square kilometres.
Angkor Wat is the best-known monument and was built in the early twelfth century under King Suryavarman II. Other major sites include Bayon, famous for its carved faces, and Ta Prohm, where trees grow among the ruins.
Angkor's water-management system helped support a large population by storing and distributing water. The city was not simply a collection of temples; it was a complex urban landscape. UNESCO listed Angkor as a World Heritage Site in 1992. The Khmer Empire's capital shifted over time, and the site was gradually reduced in importance after the fifteenth century.