San Sebastian Fortress, Fortaleza Sao Sebastiao in Portuguese, is the oldest standing fort in Portuguese East Africa and it is one of Mozambique Island’s most impressive monuments. Not only is this 16th century fortress testament to the island’s importance under Portuguese rule it harbors a clue to the population’s survival. The fort’s intricate system of rainwater collection was, until recently, the islanders only source of fresh water. Hire a local guide for roughly 1 USD and turn your tour of San Sebastian Fortress into a journey through the island’s past. View cannons from the 1820s and learn about attacks from the Dutch, Arabs, English and even the French.