Angkor Wat

Built in the early 12th century under the Khmer king Suryavarman II, Angkor Wat originally honoured the Hindu god Vishnu before being gradually converted to Buddhist use after the 13th century. Covering some 162 hectares, it is the largest religious structure ever constructed, designed as a representation of Mount Meru, the home of the gods in Hindu and Buddhist cosmology — its five central towers represent the mountain's peaks, and the surrounding moat represents the cosmic ocean. On the spring equinox, the sun rises directly over the central tower when viewed from the western entrance causeway.

Angkor Wat sits within the much larger Angkor archaeological complex, the capital of the Khmer Empire until its decline in the 15th century. Tree-ring and sediment studies published in the 2000s suggest the empire's elaborate hydraulic network of canals and reservoirs — engineered to manage the monsoon — was overwhelmed first by decades of severe drought and then by intense monsoon flooding, contributing to the city's abandonment alongside warfare and a religious shift toward Theravada Buddhism. Some researchers have proposed that the layout of Angkor's major temples mirrors the constellation Draco, a claim dismissed by most archaeologists as a modern retrofit onto an arbitrarily large dataset of temples.