The 12th-century Prasat Puay Noi is the largest and most interesting Khmer ruin in northern Isan. About the size of Buriram’s Prasat Meuang Tam but far less intact, the east-facing monument comprises a large central sandstone sanctuary surmounted by a partially collapsed prang (Khmer-style stupa) and surrounded by laterite walls with two major gates. There are still some excellent carvings intact, including Shiva riding his bull Nandi on the pediment on the back of the 'library'. It's not accessible by public transport.