When King Yasovarman I (r 889-910) moved the capital to Angkor proper, he built Phnom Bakheng as his capital. The temple, a 65m five-tiered pyramid, is a study of Hindu numerology. At the summit, five towers form a quincunx to echo the five peaks of the heavenly mountain. At its most magnificent, the pyramid was surrounded by 108 towers representing the 27 days of four lunar cycles.
An ascending temple of towers, this is a great place to view the rise and fall of the sun over the distant Angkor Wat. However, a gazillion others try to do the same so it can be rather frustrating to get that money shot.