Fort Pickens is the largest of four forts built to defend Pensacola Bay, Florida and its navy yard. The fort was begun in 1829, completed in 1834, and used until the 1940s. Built in the age of wooden warships and cannons firing round balls, the fort underwent changes in response to changes in weaponry following the Civil War. Ten concrete gun batteries, including one in the middle of the old 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 Two, and the Army abandoned the forts. Following extensive repairs by the National Park Service, the fort was reopened in 1976.
Fort Barrancas sits on a bluff overlooking the entrance to Pensacola Bay. The natural advantages of this location have inspired engineers of three nations to build forts. The British built the Royal Navy Redoubt here in 1763 of earth and logs. The Spanish built two forts here around 1797. Bateria de San Antonio was a masonry water battery at the foot of the bluff. Above it was earth and log Fort San Carlos de Barrancas. American engineers remodeled the water battery in 1838 and built a masonry fort on the bluff between 1839 and 1844, connected by a tunnel to the water battery. This is the current Fort Barrancas. A $1.2 million, eighteen-month restoration project led to its reopening in 1980.