Fort Sultan Bin Saif, Nizwa, Oman, Middle East

Montjuic Castle old military fortress on Montjuic Mountain overlooking the city, Barcelona, Catalonia, Spain, Europe

Fira, Santorini, Cyclades Islands, Greece, Europe

Downward street in Bukavu, Democratic Republic of the Congo, Africa

Girl walking through old street, Piran, Slovenia, Eastern Europe, Europe

Jabrin, Oman, Middle East

Inside Daugbjerg limestone mines near Viborg, Jutland, Denmark, Europe

Side view of houses beside a cobblestone pavement, Burford, England

An empty narrow tunnel or corridor, a passenger airbridge.