Portugal, Lisbon, Belem Tower, 16th-century fortification that served as a point of embarkation and disembarkation for Portuguese explorers and as a ceremonial gateway to Lisbon, the tower symbolizes...

Portugal, Lisbon, Belem Tower, 16th-century fortification that served as a point of embarkation and disembarkation for Portuguese explorers and as a ceremonial gateway to Lisbon, the tower symbolizes...

Portugal, Lisbon, Belem Tower, 16th-century fortification that served as a point of embarkation and disembarkation for Portuguese explorers and as a ceremonial gateway to Lisbon, the tower symbolizes...

Portugal, Lisbon, Belem Tower, 16th-century fortification that served as a point of embarkation and disembarkation for Portuguese explorers and as a ceremonial gateway to Lisbon, the tower symbolizes...

Spain, Castile and Leon, Avila, Avila Cathedral tower viewed from the walkway along the interior perimeter of the city walls that were built from 1090 onwards and are among the best-preserved and most...

Spain, Castile and Leon, Avila, The Puerta del Rastro is a monumental gate, it is part of the city walls that were built from 1090 onwards and are among the best-preserved and most complete in Europe.

Spain, Castile and Leon, Avila, City walls that were built from 1090 onwards and are among the best-preserved and most complete in Europe, viewed from the walkway along the interior perimeter of the w...

Spain, Castile and Leon, Avila, City walls that were built from 1090 onwards and are among the best-preserved and most complete in Europe, viewed from the walkway along the interior perimeter of the w...

Spain, Castile and Leon, Avila, City walls that were built from 1090 onwards and are among the best-preserved and most complete in Europe, viewed from the walkway along the interior perimeter of the w...

Spain, Castile and Leon, Avila, City walls with the brick steeple of the former Carmelite convent El Carmen above the Puerta del Carmen viewed from the walkway along the top perimeter of the walls.

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.

Spain, Castile and Leon, Avila, City walls that were built from 1090 onwards and are among the best-preserved and most complete in Europe, section of walls known as the the Paseo del Rastro.