Known as the Grand Canyon of Thailand, Sam Phan Bok, translated as 3000 holes, owed its name to the multiple basins along the 5km long rock reef in Mekong River. The rock holes of different shapes and sizes are carved out by thousands of year of erosion, appearing only during drought seasons. Visitors can hire boats from Haad Saleung to view Sam Phan Bok and other features along Mekong River such as a narrow river channel Pak Bong, and Haad Hong and Haad Hin Si beaches.