O'Brien's Tower is a circular stone tower which is about halfway up cliffs. It was built by Sir Cornelius O'Brien in 1835 as a lookout for tourists who flocked to the place at that time. From the top of the lookout you can see the Aran Islands, Galway Bay, and in the background the mountains in Connemara Maumturk. O'Brien also built a wall of flagstones along the Cliffs of Moher and is said in the town that he built everything in the area except the cliffs. If I remember right, a climb up the tower costs £ 6.