Prasaat Phanom Rung and Muang Tam are located in Buriram.
Prasaat Phanom Rung is one of the most significant Khmer monuments in Thailand. It was built in the 10th-13th century A.D. Phanom Rung was a Hindu Saivite (Shiva) monastery. Sculptures also present images of Vishnu. A processional way leads through Naga bridges to the main sanctuary. Lintels, pediments depict the Hindu Gods Brahma, Vishnu and Shiva, with also scenes of the Ramayana. The most famous lintel (Vishnu Anantasayin) depicts Vishnu reclining on the back of the Naga King Ananta. This lintel disappeared for many years outside the country, but was recently returned.
The setting of Phanom Rung is quite scenic, with views of the countryside all around. The site is probably the most visited Khmer monument in Thailand. If you want it quieter, be sure to arrive before 10 A.M.
Muang Tam ('low city') is located nearby, and is worth a visit all by itself. Around its main structure, five 'brick' towers and ponds with lotus flowers are present. There is not much supervision and school children seem to use the area as a playing ground.