The great tourist ritual of Angkor involves climbing up Bakheng Hill to see the sun setting over Angkor Wat and the surrounding forest (either on foot or by elephant). While you are up there, be sure to visit the mountain-temple devoted to Shiva built atop Phnom Bakheng. It was the first great building erected by Yasovarman I when he left Hariharalaya (Roluos Group) to establish his capital in Angkor (late 9C - early 10C).