The Rock of Gibraltar provides Food and Gold bonuses to the city that works it. However, it is sometimes located far away from land, which can make it impossible to found a city close enough to work the wonder. Like a mountain, the tile it occupies can only be entered by a Helicopter Gunship, which does not sustain damage if left there.
Gibraltar is a peninsula containing a remarkable rock formation at the mouth of the Mediterranean Sea. Captured from Spain by the English and Dutch in 1704 and ceded to England in 1713, Gibraltar has been a British possession ever since (much to the annoyance of Spain, which wants it back). Commanding the entrance to the Atlantic from the Mediterranean, Gibraltar has been a major British naval base for three hundred years. Most of Gibraltar is covered by the "Rock," a huge formation of shale, sandstone and limestone thrust up by the unimaginable power of plate tectonics. The Rock stands some 430 meters (1400 feet) in height. At one time Gibraltar was a massive fortification allowing Britain to dominate the narrow Mediterranean-Atlantic passage, but today the island is more of a nature preserve and tourist destination than it is a military base.