The Roulos Group are the oldest temples in the complex and include Prasat Bakong, Preah Ko, and Lo Lei all of which date back to 879- 893. The most impressive of the three remaining temples is Prasat Bakong, a five-stepped pyramid temple dedicated to King Indravarman. The corners of the pyramid have statues of elephants and crouching lions guard the steps. Many architectural innovations were created here, in particular the arched gateway or gopura. Proceed to the hilltop temple of Phnom Bakheng and climb the imposing remains for a truly memorable sunset.