Koh Ker Temple.

The temple complex at Koh  ker  represents the remnants of the capital of the Khmer Empire from the time the Khmer capital was first moved to the Angkor area in the late 9th century. It remained there for almost 500 years, with a brief interruption only a few decades later. In 928 A.D., King Jayavarman IV, possibly a usurper to the throne, created this impressive royal city of Brahmanic monuments and temples only 100km away.

The premier ruin of the complex is Prasat Thom, an imposing 7-tiered pyramid and temple complex.There  are  several  nicely preserved ruins with small temple  complexes.  Lingas are still in place in some monuments such as Prasat Balang and Prasat Thneng.

A trip to Koh Ker takes the better part of a day out of Siem Reap  and  is usually combined with a visit to Boeng Mealea.