
The Giant's Causeway, Northern Ireland's most popular tourist attraction, is composed of basalt rock columns formed over 50 million years ago by volcanic activity.
(Courtesy Seamus Loughrey)More Photos
In 1986, the Giant's Causeway became one of 878 cultural and natural heritage properties considered a World Heritage site by UNESCO -- the United Nations, Educational, Scientific and Cultural Organization.
The Giant's Causeway is Northern Ireland's most popular tourist destination, attracting more than 750,000 visitors in 2008.
For more information on the Giant's Causeway and Ireland visit: www.discoverireland.com.