Spain, Castile and Leon, Avila, City walls that were built from 1090 onwards and are among the best-preserved and most complete in Europe, looking along the northern section of the walls.

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.

Northern Ireland, County Fermanagh. Monea Castle, a 17th century Plantation rectangular tower house.

Northern Ireland, County Fermanagh. Monea Castle, a 17th century Plantation rectangular tower house.

Northern Ireland, County Fermanagh, Irvinstown, Garden of the Celtic Saints, St Patrick.

Northern Ireland, County Fermanagh, Irvinstown, Garden of the Celtic Saints, Saint Molaise.

Northern Ireland, County Fermanagh, Irvinstown, Garden of the Celtic Saints, The Penal Crucifix.

Northern Ireland, County Fermanagh, Irvinstown, Garden of the Celtic Saints, Celtic Cross.

Northern Ireland, County Fermanagh, Irvinstown, Garden of the Celtic Saints, Oisin returns from Tir na nOg.