UK - Giant's Causeway

Stamp Issue: 24 Jun 1981 （Honeycomb）

Stamp Issue: 8 Jun 1999?

Stamp Issue：16 Mar 2004 （Antrim Parlour）

Stamp Issue：11 Mar 2008 （Wishing Chair in the Honeycomb）

The Giant's Causeway (or Irish: Clochán na bhFómharach) is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption. It is located on the northeast coast of Northern Ireland, about two miles (3 km) north 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. 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 and eight sides. The tallest are about 12 metres (36 ft) high, and the solidified lava in the cliffs is 28 metres thick in places.
During the Paleogene period, Antrim was subject to intense volcanic activity, when highly fluid molten basalt intruded through chalk beds to form an extensive lava plateau. As the lava cooled rapidly, contraction occurred. While contraction in the vertical direction reduced the flow thickness (without fracturing), horizontal contraction could only be accommodated by cracking throughout the flow. The extensive fracture network produced the distinctive columns seen today. The basalts were originally part of a great volcanic plateau called the Thulean Plateau which formed during the Paleogene period.