Bakong is the first major temple-mountain built by the Khmer in the 9th century, serving as the prototype for all later temple-mountains including Angkor Wat. Built under King Indravarman I as the state temple. Its five-tiered pyramid represents the sacred Mount Meru. Part of the Roluos Group containing the oldest Angkor temples. The temple is surrounded by a moat and guardian stone lions, offering insight into early Khmer architectural development before the Angkor period reached its zenith.