Angkor Wat was built in the 12th century as a Hindu temple, like most of the Siam Reap temples. It was then populated with Buddhas in the 13th century, then the Buddhas were hacked up by a subsequent Hindu king, then partially restored as the country permanently became Buddhist. What the Hindu king didn't desecrate treasure hunters carted off after it was rediscovered, so the overall aesthetic is of a Hindu temple decorated with headless Buddhas. The very general idea is that the tower complex at the center of the temple is supposed to be Mount Meru, where the Hindu gods reside, and then the city was organized around this base.