The Rock of Gibralter has been held by Britain since its capture from Spain in 1704. The rock itself is part of a huge overturned fold of Jurassic shale and limestone. Gibraltar is connected to the mainland of the Iberian Peninsula by a huge tombolo. A tombolo is sand spit that connects an offshore island to the mainland. Today most of the tombolo at Gibraltar is covered in houses, shops and apartment buildings, but you can see the original sediment of the sand spit and some sand dunes preserved along the Straits of Gibraltar in a small area along the beach within the kind of no-man's land that exists along the fence between Spain and Gibraltar.
Sand spits and tombolos are created by waves and winds that transport sediment along beaches, so they mostly lie very near to sea level. The Gibraltar tombolo is no different---the maximum elevation of the land in La Linea---the Spanish city built right up to the border with Gibraltar, is about 3 feet above sea level.
About 65,000 people live in La Linea today. Mostly likely by the year 2100 the town will be abandoned due to sea level rise. Wave action will continue to deposit sand on the tombolo as sea level rises, and eventually La Linea will disappear beneath the sands of a new tombolo. If no new construction is allowed on the new tombolo, the view of Gibraltar from Spain in the year 2150 may look much as it did in 1782, when the tombolo was fully exposed, and John Mace painted a picture showing the view of Gibralter from Spain.
The tombolo at Gibraltar as it appeared in 1782
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