GIBRALTAR IS AN overseas territory of the United Kingdom. Historically known as 1 of the Pillars of Hercules, the Rock of Gibraltar has guarded the entrance to the Mediterranean world since the beginning of Western civilization. Held by Great Britain since 1704 (formally since 1713), the peninsula remains 1 of Britain’s last overseas territories, with little indication of change in the near future, despite intense pressure by the Spanish government. The Rock is situated at the end of a peninsula, 2.8 mile (4.4 kilometer) in length, that juts out into the Alborán Sea (the westernmost extension of the Mediterranean Sea), terminating in Europa Point. The other “pillar,” Cape Ceuta (or Punta Almina), lies 9 mile (14.5 kilometer) across the Strait of Gibraltar, on the north coast of Africa. To the west are the more protected waters of the Bay of Algeciras, and the man-made Gibraltar Harbor, around which rises the military and administrative community of the colony. The eastern face of the rock is much more perpendicular, as are the northern and southern approaches, underlining the defensive importance of the rock, which itself is composed of dense limestone arranged in thick rock beds. Gibraltar is connected to the mainland of Spain by a narrow isthmus, low and sandy, across which daily migrants travel from the nearby Spanish town of La Línea. The Rock has been extensively fortified and modified over the centuries, with about 10 mile (16 kilometer) of tunnels, casements for heavy artillery (especially during World War II), a canal cut across the isthmus, and even a narrow landing strip jutting into the Bay of Algeciras on the western side of the peninsula. The naval harbor and dockyard has recently been expanded with a land reclamation project called the Europort, increasing Gibraltar’s total land area by 10 percent. Having no flat land of any consequence, Gibraltar must import all of its food needs. The colony’s economy depends instead on tourism, offshore banking and finance, and industries related to shipping.