Preah Khan, or 'Sacred Sword,' is a massive Buddhist temple complex built by King Jayavarman VII in 1191 to honor his father. The complex covers 56 hectares and is surrounded by a moat, once housing nearly 100,000 people including 1,000 teachers and 1,000 dancers. The temple showcases a unique blend of Buddhist and Hindu architecture, with a two-story Greek-style structure that is unique in Angkor. Much of it remains deliberately unrestored, preserving a mysterious atmosphere with trees and vegetation growing among the ruins.