Located in Udon Thani province, Phu Phra Bat Historical Park is most renowned for its rock formations that dot its sylvan hill terrain. Most of these stone formations are caves which over thousands of years have acted as shelter to various civilizations; traces of prehistoric man have been found in addition to the presence of Khmer and Dvaravati people.
Phu Phra Bat Historical Park has many stone formations, for instance, mushroom-like formation where a heavier rock is balanced on a small chunk of sandstone. The stone formation to which legend of Nang Usa is attached asks for a special mention; here a princess named Nang Usa was imprisoned by her father. The story ends well when garland sent by the princess is discovered by a prince who tracks down her whereabouts and falls in love with her.
In addition to many other rock formations which include boulders and spires, the place is also known for its temples belonging to the Dvaravati era that contains Buddha images plus caves that contain 6000 years old pre-historic art paintings. Human figures, animals and geometric shapes can be found in these paintings which are located at Tham Woau and Tham Khon.