The Giant's Causeway is one of Ireland's most renowned landmarks. Comprising approximately 40,000 interlocking basalt columns, it's the result of an ancient volcanic fissure eruption. Visitors ...

In Northern Ireland, we have a diverse range of rock forms. Basalt rock comprises most of County Antrim’s geological map, while sandstone and slate comprise most of Down and some of Armagh.

I'm in Northern Ireland, at a place called the Giant's Causeway. There are about 40,000 of these columns made of a really hard rock called Basalt, all fitting together like an enormous puzzle.