Kabah Ruins

The Kabah Ruins were a shipwreck site located in the Navassa region of the Caribbean. A complex of sunken Mayan ruins inhabited by several hostile species, including sharks and moray eels, they were explored by the pirate Edward Kenway during the early 18th century.

While searching the remnants of Mayan architecture and the nearby shipwreck, Edward managed to locate and loot several sunken treasure chests, gaining money and an upgrade plan for his own vessel, the Jackdaw.

Reference

 * Assassin's Creed IV: Black Flag