Located in the mountainous area of Sap – Ba The in Thoai Son District, An Giang Province, about 30 from Long Xuyen, Oc Eo Remains Site is a large area ancient vestige of the Phu Nam Kingdom, which was a powerful nation in the Southeast Asia around two thousand years ago. This ancient citadel of OC - Eo used to be a commercial center in the Middle Ages.