Designated a UNESCO World Heritage Site in 1996, Säo Miguel fort was built in 1576 by Paulo Dias de Novais who founded the city of Luanda. In 1627, the fort became the administrative colony and was a major outlet for slave traffic to Brazil. With thick walls fitted with cannons, it was a fortified enclosure, and it remained the headquarters of the Commander-in-Chief of the Portuguese Army in Angola until 1975. The fort presently houses the National Museum of Military History. http://afrotourism.com/attraction/fortaleza-de-sao-miguel-saint-michaels-fortress/