Spain, Castile and Leon, Avila, City walls with the circular Avila Cathedral built into the walls that were built from 1090 onwards and are among the best-preserved and most complete in Europe.

Spain, Castile and Leon, Avila, The Puerta de San Vicente or Gate of St Vincent is a monumental gate with very strong turrets flanking the entrance, it is part of the city walls that were built from 1...

Spain, Castile and Leon, Avila, The Puerta de San Vicente or Gate of St Vincent is a monumental gate with very strong turrets flanking the entrance, it is part of the city walls that were built from 1...

Spain, Castile and Leon, Avila, The Puerta de San Vicente or Gate of St Vincent is a monumental gate with very strong turrets flanking the entrance, it is part of the city walls that were built from 1...

Spain, Castile and Leon, Avila, The Puerta de San Vicente or Gate of St Vincent is a monumental gate with very strong turrets flanking the entrance, it is part of the city walls that were built from 1...

Spain, Castile and Leon, Avila, The Puerta de San Vicente or Gate of St Vincent is a monumental gate with very strong turrets flanking the entrance, it is part of the city walls that were built from 1...

England, Devon, Dartmouth Castle, Fortified towers and castle exterior forming part of the sea wall.

Ireland, County .Westmeath, Moate, Dun na Si Heritage Park, Reconstruction of a Ring Fort.

Republic of Ireland, County Wexford, Ferrycarrig, Irish National Heritage Park, Ring Fort, General view from the interior.

Republic of Ireland, County Wexford, Ferrycarrig, Irish National Heritage Park, Ring Fort entrance.

Republic of Ireland, County Wexford, Ferrycarrig, Irish National Heritage Park, Ring Fort entrance.

Ireland, County Clare, Quin, Craggaunowen, The Living Past Experience, Reconstruction of a crannog with thatched huts in the settlement area.