O'Brien's Tower marks the highest point of the Cliffs of Moher.
It was built in 1835 by local landlord Sir Cornellius O'Brien as an observation tower for the hundreds of Victorian tourists that frequented the cliffs at the time.
On a clear day the view can extend as far as Loop Head at the southern tip of Clare and beyond to the mountains of Kerry.
Looking north from O'Brien's Tower on clear days, you can see the Twelve Bens in Connemara.
Folklore holds that Sir Cornellius O'Brien was a man ahead of his time, believing that the development of tourism would benefit the local economy and bring people out of poverty.
O'Brien also built a wall of flagstones along the Cliffs and it was said in the locality that he built everything in the area except the cliffs.
Reference: Wikipedia