evidence: Si Sa Ket - Old town Si Sa Ket - Khao Phra Viharn National Park - Prang Ku Khmer Ruins - Wat Mahaphuttaram - Wat Pa Maha Chedi Kaeo Or Wat Lan Khuat [...] As Si Sa Ket borders Cambodia, there are a number of Khmer ruins throughout the region and the History of the provincial capital is believed to date back to the Angkorian era. The greatest of these ruins in the region, and one of the most spectacular Khmer Temples ever constructed, is Preah Vihear. Phra Vihan, as it is referred to in Thai, is a temple that was constructed atop a cliffside escarpment that lies across the border in Cambodia but is far more accessible as a day Trip from Si Sa Ket, where Prasat Khao Phra Wihan national park contains a number of decent sights prior to crossing the border. [...] Travel Tips - Preah Vihear (Phra Vihan) Temple is occasionally closed as a result of border conflicts with neighbouring Cambodia.Cambodia allows day-Trip access to the Temple on a VISA-free basis from Thailand. Thailand imposes an admission fee of THB 400 for entering the national park.