The fort was begun in 1829, completed in 1834, and used until the 1940s. Geronimo spent some time in captivity there in the last two decades of the 19th century. Built in the age of wooden warships and cannons firing round balls, the fort underwent changes in response to advances in weapon technology following the Civil War. Ten concrete gun batteries, including one in the middle of the historic fort, were built from the 1890s through the 1940s, each a response to a particular threat. Atomic bombs, guided missiles, and long-range bombers made such forts obsolete by the end of World War II and the Army abandoned the forts. Following extensive repairs by the National Park Service, the fort was reopened in 1976.