Ireland, County Sligo, Gortarowey, Ben Bulben mountain with rhododendrons in the foreground.

Ireland, County Sligo, Gortarowey, Ben Bulben mountain with rhododendrons in the foreground.

Ireland, County Sligo, Gortarowey, Ben Bulben mountain with rhododendrons in the foreground.

China, Guangxi, Guilin, Limestone peaks and surrounding landscape.

Ireland, County Clare, Rocky shoreline at Black Head with small stack of rocks constructed by tourists.

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

Ireland, County Clare, The Burren, A single weathered rock sits on typical limestone landscape.

Ireland, County Clare, The Burren, Poulnabrone Dolmen, the thin capstone sits on two 6 feet high portal stones, these stones created a chamber within which the dead were placed, the people buried here...

Ireland, County Mayo, Killala, Killala Round Tower.

Ireland, County Roscommon, Roscommon town, The Roman Catholic Sacred Heart Church with a sunken grotto in the foreground.

Ireland, County Clare, The Burren, Poulnabrone Dolmen, the thin capstone sits on two 6 feet high portal stones, these stones created a chamber within which the dead were placed, the people buried here...