Ireland, County Clare, The Burren, Clint blocks of limestone and gryke or grike fissures leading to a rock boulder split in two by erosion.

Ireland, County Mayo, Downpatrick Head, Dun Briste or Broken Fort is an impressive sea stack at the headland.

USA, Utah, Moab, Base jumpers prepare to jump from the Mothership Spacenet suspended from the cliffs 950 vertical feet above the valley floor at Mineral canyon. Another jumper rides the zipline from...

USA, Utah, Moab, A base Jumper leaps off the clifftop 950 feet above the floor of Mineral Canyon.

USA, Utah, Moab, A base Jumper leaps off the clifftop 950 feet above the floor of Mineral Canyon.

USA, Utah, Moab, A base Jumper jumps off the clifftop 950 feet above the floor of Mineral Canyon.

USA, Utah, Moab, A base jumper drops from the Mothership Space Net suspended from the cliffs 950 vertical feet above the valley floor at Mineral Canyon.

USA, Utah, Moab, Base jumpers prepare to jump from the Mothership Spacenet suspended from the cliffs 950 vertical feet above the valley floor at Mineral Canyon.

USA, Utah, Moab, A base jumper descends in his parachute off the 400 foot vertical face of the Tombstone in Kane Springs Canyon. Note his shadow on the cliff.

USA, Utah, Moab, A base jumper leaps off the 400 foot vertical face of the Tombstone in Kane Springs Canyon. He has deployed his pilot chute. Note his shadow on the cliff.

USA, Utah, Moab, A base jumper leaps off the 400 foot vertical face of the Tombstone in Kane Springs Canyon. He has deployed his pilot chute. Note his shadow on the cliff.

USA, Utah, Moab, A base jumper leaps off the 400 foot vertical face of the Tombstone in Kane Springs Canyon. Note his shadow on the cliff.