Named for the sacred sword owned by the 9th-century King Jayavarman II, the Preah Khan temple complex was built by Jayavarman VII (r.1181–1215). It is believed to have functioned as his temporary capital while Angkor Thom was being restored after it was sacked by the Cham in 1177. It also served as a monastery and religious college with over 1,000 teachers. An inscribed stone stela found here in 1939 indicates that the temple was based at the center of an ancient city, Nagarajayaciri – jayaciri means sword in Siamese. Originally dedicated to the Buddha, this temple was later vandalized by Hindu rulers who replaced many Buddha images on the walls with carvings of numerous Hindu deities.

Today, the complex extends over a sprawling 2 sq miles (5 sq km), and is surrounded by a 2-mile (3-km) long laterite wall. The central sanctuary is accessible through four gates set at the cardinal points. One of the main highlights is the Hall of Dancers, named for the apsara bas-reliefs that line the walls. The premises also has a massive baray (reservoir). The most notable temple in the complex is the Temple of the Four Faces. Similar to Ta Prohm, Preah Khan is studded with great trees whose roots cover and, in places, pierce the laterite and sandstone structures over which they grow. Unlike Ta Prohm, however, the temple is undergoing restoration by the World Monuments Fund, and many of the trees have now been cut down.