Sam Pan Bok (Thai: สามพันโบก) is a seasonal attraction and also known as the "Grand Canyon of Thailand" and is the biggest rock reef in the Mekong River. Sam Phan Bok is a group of sandstone that has been eroded by stream from the Mekong River every rainy season until this area has more than 3,000 Bok with countless basins and potholes. [1] It is located 700km from Bangkok.[2] Sam Phan Bok translates as '3,000 shallow lakes'.[3] Sam Pan Bok is in northeastern Thailand (Isan), on the bank of the Mekong. Administratively, it is in Baan Phong Pao, Lao Ngam Sub-district, Pho Sai District, Ubon Ratchathani Province.[4] The holes in the sandstone rocks had developed over millions of years.[4] There are different sections of Sam Phan Bok including Hat Hong, Pak Bong and Lak Sila Lek.[4]