The Great Siege Tunnels, the Rock and Gibraltar's Military Heritage
Gibraltar's military heritage is the most intensively layered of any comparable territory in the world: fortifications, tunnels, batteries, and gun emplacements occupy almost every prominent position on the Rock, and the underground military infrastructure built into the limestone represents centuries of investment by successive garrison powers. The Great Siege Tunnels, blasted into the upper Rock between 1779 and 1783 during the 14th and longest Great Siege of Gibraltar, were the first tunnels cut for artillery in military history and are still partially accessible as a visited heritage site. The World War II tunnels, a much larger network running for 50 kilometres through the Rock and capable of sheltering the entire garrison, were cut at extraordinary speed in 1940-41 and served as the forward headquarters for Operation Torch, the Allied invasion of North Africa in 1942. The Windsor Gallery within the tunnel system preserves the wartime headquarters in period condition. The Upper Rock Nature Reserve, accessed by cable car from the southern end of Main Street, contains the O'Hara's Battery, the Moorish Castle dating to 711 AD, and the barbary macaque colony whose presence is protected by a superstition linking their continued habitation to British sovereignty over the territory.