Built by Jayavarman VII in 1191, the name of the temple means "Sacred Sword." It's rumored that this was where Jayavarman called home during the building of the Bayon. You approach the Preah Khan through a walkway lined with low lantern towers (note that the Buddhist reliefs were changed to divine vultures during the iconoclastic period). The compound is surrounded by wall and moat. The moat represents the ocean, the wall is a mountain, and the temple is Mount Meru -- the mother mountain of Hindu creation. Four gates face the ordinal directions, and each gate has a God and Demon statue like entry to Angkor Thom but just a tower, no Apsara face. Stop in at the small visitor center for information about preservation. The temple is a monastery, like Ta Prohm and Banteay Kdei, and is thought to have been built in homage to Jayavarman's father. The site plan is much like Ta Prohm. The temple passage has lots of meandering galleries and side rooms with statues (most broken or missing) and Shiva Lingam. Many Buddha reliefs here have been chiseled off. Interior walls are lined with cross-legged, bearded forest hermits in relief. The central tower is a stupa for ashes of a later king, dating from the 16th century and replacing a large Buddha statue of Jayavarman VII that was found by the French in 1943, then summarily lost. The many empty pedestals and lintels are courtesy of the Khmer Rouge and many tomb raiders.
Enter the temple from the west, then make the long and winding walk along the central axis, exiting through the east gate where you'll see a massive spoong tree (like a banyan tree). From here, make your way back through to the west entrance and your transport.