 Many of Gibraltar's fortifications were already redundant well before the British garrison was withdrawn from the territory in the 1990s, and the rapid military rundown in the 1980s and the 1990s left the civilian authorities with a large amount of surplus military property. Many of the best-preserved fortifications are in the Upper Rock Nature Reserve, a conservation area that covers about 40 % of the area of Gibraltar. A few of the Upper Rock batteries have been preserved intact; all three of the 5.25-inch guns at Princess Anne's Battery are still in place, making it the only place in the world where a complete 5.25-inch battery can still be seen. The 9.2 inch guns at Breakneck, Lord Airey's and O'Hara's Batteries are still in situ and can now be visited. Elsewhere, most of the ordnance has been removed. Two surviving 6-inch guns remain at Devil's Gap Battery, one of which is the gun that engaged a German U-boat in August 1917. At Napier of Magdala Battery one of the two 100-ton RML 17.72 inch guns is still in situ and has been restored, along with a 3.7 inch quick-firing anti-aircraft gun. The site is now run by the Gibraltar Tourist Board in conjunction with the Nature Reserve.
