The temples, and in fact the whole area, is commonly called Angkor Wat, although that's only the largest of the many temples. (As an aside, the real town name of Siam Reap translates into something like Destroy the Thais, which is very welcoming.) Siam Reap served as the capital of the Cambodian empire from the 900's, although different kings built different cities/palaces/temples in the same general area, which accounts for the huge spread of ruins at the site today. The site was abandoned either because it was destroyed by the Thais, or because it ran out of water, and was left to fall apart in the jungle, which, as you'll see later gives some great Indiana Jones/Lara Croft type pictures. In the 19th century a French explorer stumbled across it, and Siam Reap's tourism boom got underway.