Facing Mafia Island on Tanzania’s south coast mainland, Kilwa Masoko is famous for its UNESCO world heritage “Kilwa ruins” and for its crystal clear waters full of marine life. The sea is always accessible from the pristine, white sandy beaches for swimming and snorkeling even at low tide. Kilwa Masoko is the site of very impressive ruins from the Ottoman Arab dynasties, the most important of about thirty-five trading sites on the Indian Ocean during the 11th through 16th centuries AD. Archaeological investigations at the site began in earnest in 1955, and the site and its sister port Songo Mnara were named Unesco World Heritage site in 1981. The area offers travelers the opportunity to explore the history of the region and even visit archaeological underwater sites.