Forts

thumb|Castillo San Felipe del Morro, Puerto Rico. The fortress and walled city of [[Old San Juan are a UNESCO World Heritage Site.]]

19th century Belarusian fortress

thumb|Ribat of Monastir, [[Tunisia]]

ancient fortress in Jerusalem

fort

castle in Kirkuk, Iraq

fortification, usually dating from the Iron Age

building in Tanzania

stone enclosure with vitrified walls

thumb|upright|Aerial view of the fort of Madama, November 2014 Madama is a border settlement on the northeast frontier of Niger. Little more than an army post, the settlement serves as a frontier station controlling travel between Niger and Libya. It is also the site of a former French colonial fort, built in 1931. The fort is now surrounded by barbed wire and a field of landmines. thumb|View on Fort Madama from the North, June 2017

Venezuelan military base

fort of the English East India Company at Saint Helena