The cliffs are 320 MILLION years old.
Ancient rivers laid down sediments on the sea bed to form the rocks of the Cliffs of Moher – sandstone, siltstone and shale.
The Cliffs of Moher are 702 feet high and span across eight miles along the Wild Atlantic Way. The highest point and the best views are at Knockarden, near O’Brien’s Tower, which was built by Cornelius O’Brien in 1835.
They are not the highest cliffs in Ireland but the Cliffs of Moher are the steepest, due to the type of rocks.
And perhpas most interesting for modern times readers, the cliffs were the site of a few sets from Harry Potter Chamber of Secrets.