A detail map of the Rock of Gibraltar in 1920, showing the area under British control, the neutral zone with Spain, and the town of Linea (La Linea de la Concepcion). This map includes O'Hara's Tower, the Moorish Castle, Breakneck Stairs, King's Bastion, Europa Point, the Moorish Wall, the Military Prison, and the Governor's Grounds near the neutral zone with its race track, cattle sheds, vegetable gardens, and cemetery.