The Giant's Causeway (Irish: Clochán an Aifir) is an area of approximately 40,000 interlocking basalt columns, the result of an ancient volcanic fissure eruption, part of the North Atlantic Igneous Province active in the region during the Paleogene period. It is located in County Antrim on the north coast of Northern Ireland, about three miles (4.8 km) northeast of the town of Bushmills.
It was declared a World Heritage Site by UNESCO in 1986 and a national nature reserve by the Department of the Environment for Northern Ireland in 1987. In a 2005 poll of Radio Times readers, the Giant's Causeway was named the fourth-greatest natural wonder in the United Kingdom.
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