Fortifications of Gibraltar and Great Siege Tunnels
Most of the defensive buildings atop the Rock were constructed by the British in the early 19th century. The graffiti found on some interior walls was scribbled by soldiers trying to stay awake while on duty (falling asleep was then punishable by death). The Great Siege Tunnels, carved out of solid limestone with hand tools, were conceived as a way to install guns on the face of the Rock. After you tour, head outside to see the Rock’s famous tailless monkeys, the Barbary apes.