thstrand posted a photo:
A distant view of O'Brien's Tower observatory at the Cliffs of Moher, Ireland. The 19th-century observation tower was built in 1835 by local landowner and Member of Parliament, Sir Cornelius O’Brien. The tower is located at the highest point of the cliffs. The vertical face displays clear strata of dark shale and lighter sandstone, with the oldest rocks at the bottom. The site is near Liscannor in County Clare, Ireland.

© thstrand