Giant's Causeway, Antrim, Northern Ireland

The Giant's Causeway is a UNESCO World Heritage Site and worthy of a visit, especially if the weather is fine. Comprising of over 40,000 basalt columns that were created when volcanic lava made contact with the sea, cooled rapidly and cracked into these geometrical shapes. Almost all are six-sided, although there are a few 4 and 5 sided columns as well.
Located a few miles west of Bushmills (famous as world's oldest whiskey distillery!!!) and a few more miles east of Ballycastle in north county Antrim, the causeway is well signposted.
It is better if visited mid-week and early in the day when you will enjoy almost uninterrupted access. There is a well stocked visitor centre about half a mile from the site and buses shuttle visitors along the coastal route. The best way to experience it (like most places worlwide) is forget the bus, and stoll down the shore path, follow the route marker signs to the very end and then return along the cliff top walk which affords views east to Scotland and west ot Donegal if the weather is clear.