North bank of the Douro River, UNESCO World Heritage Site, Porto, Norte, Portugal, Europe

Church of Sant'Apollinare and portico, Tresigallo, Emilia-Romagna, Italy, Europe

Chrisopigi Monastery, Sifnos Island, Cyclades, Greek Islands, Greece, Europe

The Walls of Dom Fernando (Fernandine Walls) above the Douro River, Porto, Norte, Portugal, Europe

Amoreira Aqueduct (Aqueduto da Amoreira) built on foundations of a Roman aqueduct, in the town of Elvas, Alentejo, Portugal, Europe

Old Parliament Building now the Presidential Secretariat offices and modern skyscrapers, Colombo, Sri Lanka, Asia

Ancient ruins of a Gothic abbey under a clear blue sky at Byland Abbey, North Yorkshire, England, United Kingdom, Europe

A corner townhouse on Main Street, typical colonial architecture of Gibraltar, Europe

Tilbury Fort, Tilbury, Essex, England, United Kingdom, Europe

View towards St. Paul's Cathedral, London, England, United Kingdom, Europe

Titanium facade of the Guggenheim Museum designed by Frank Gehry, Bilbao, Basque Country, Spain, Europe

Park Guell, UNESCO World Heritage Site, Barcelona, Catalonia, Spain, Europe

Leeds Castle near Maidstone, Kent, England, United Kingdom, Europe

Blue Mosque (Sultanahmet) at twilight, UNESCO World Heritage Site, Fatih District, Istanbul Province, Turkey, Europe

St. Mary the Virgin Church, dating from the 1760s, Glynde, East Sussex, England, United Kingdom, Europe

Aerial drone panoramic view of the Alcobaca Monastery (Alcobasa Monastery), UNESCO World Heritage Site, a Catholic monastic complex, Alcobaca, central Portugal, Eurpe

The Bell Tower of St. Arnir, Split, Croatia, Europe

Woman posing at Fisherman's Bastion, UNESCO World Heritage Site, Budapest, Hungary, Europe

View of Saint Demetrius Cathedral, Berat, Albania, Europe

A view of the Russian Orthodox Solovetsky Monastery founded in 1436 by two monks on Bolshoy Island, UNESCO World Heritage Site, Onega Bay, Arkhangel Oblast, Russia, Arctic, Europe

Ceiling and Walls, Interior, Blue Mosque (Sultan Ahmed Mosque), 1609, UNESCO World Heritage Site, Sultanahmet, Istanbul, Turkey, Europe

Architectural detail of the western face of the Zytglogge, a landmark medieval tower built in the 13th century, Bern, Switzerland, Europe

Litomerice old town hall converted into a Museum, Litomerice, Bohemia, Czech Republic (Czechia), Europe