Gibraltar is a rocky promontory on the southern coast of Spain that has been a British colony since 1704. During the Second World War it was a key Allied outpost due to its strategic position at the entrance to the Mediterranean Sea and the fact that it was the only remaining Allied foothold on continental Europe. Gibraltar was the home port for a small, but powerful, British Fleet - Force H - between 1940 and 1943. It was also a staging point for Mediterranean convoys heading for Malta and Egypt, and, when an airfield was constructed in 1942, was also a key transit point for Allied aircraft. Over 40 km of tunnels were excavated in the rock of Gibraltar to house logistic stores, barracks and command centres and these tunnels were the site of the headquarters that planned the Allied landings in North Africa in November 1942. Gibraltar was considered extremely vulnerable to Spanish military action, and Hitler coveted it as a means to control the Mediterranean. Despite German pressure, however, Spain remained neutral throughout the war and Gibraltar, although bombed on numerous occasions, was never threatened.