The Giant's Causeway is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption. It is also known as Clochán an Aifir or Clochán na bhFomhórach in Irish and tha Giant's Causey in Ulster-Scots.
It is located in County Antrim on the northeast 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 in 1987 by the Department of the Environment for Northern Ireland.
The site first became popular with tourists during the nineteenth century, particularly after the opening of the Giant's Causeway Tramway, and only after the National Trust took over its care in the 1960s were some of the vestiges of commercialism removed. Visitors can walk over the basalt columns which are at the edge of the sea, a half-mile walk from the entrance to the site.