<Tr> <Th> Region </Th> <Td> Europe </Td> </Tr> <Tr> <Td_colspan="2"> Location of Giant's Causeway and Causeway Coast in Northern Ireland </Td> </Tr> <P> The Giant's Causeway is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption . 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 . </P> <P> It was declared a World Heritage Site by UNESCO in 1986, and a national nature reserve in 1987 by the Department of the Environment for Northern Ireland . In a 2005 poll of Radio Times readers, the Giant's Causeway was named as the fourth greatest natural wonder in the United Kingdom . The tops of the columns form stepping stones that lead from the cliff foot and disappear under the sea . Most of the columns are hexagonal, although there are also some with four, five, seven or eight sides . The tallest are about 12 metres (39 ft) high, and the solidified lava in the cliffs is 28 metres (92 ft) thick in places . </P>

Where is the giant's causeway in northern ireland