San Gimignano at sunrise. Siena province, Tuscany, Italy

Tre Cime di Lavaredo seen on the south side, Auronzo di Cadore, Belluno, Veneto, Italy

Merchants houses, Old Market square, Poznan, Poland, Eastern Europe

Cheyney Court, Winchester, Hampshire, England, UK

Pedestrians passing by street art mural NosotrasJuntas by Madrid artist Spok Brillo on Gran Via in Madrid, Community of Madrid, Spain

UK, England, Northumberland, Hexham, Henshaw, Hadrian's Wall, Sycamore Gap

UK, England, Northumberland, Hexham, Henshaw, Hadrian's Wall, Sycamore Gap

Local architecture in Bielsko Biala, Silesian Voivodeship, Poland

Alanya Harbour and The Red Tower, Alanya, Turkey

Sprinkenhof office building built in 1927-1943 in brick expressionist style, Kontorhausviertel, Hamburg Altstadt, Hamburg, Germany

Spain, Galicia, Lugo Roman walls and cathedral illuminated at night

Colourful Palenqueras selling fruits on the walls of Cartagena, Bolivar Department, Colombia (MR)

Ota Darvoza, the western gate to the old town of Khiva. A UNESCO World Heritage Site, Uzbekistan

Castelo dos Mouros ramparts, Sintra, Portugal,

View from Baluarte de Santa Llucia to D'Alt Vila, Ibiza, Balearic Islands, Spain

Croatia, Dubrovnik, Boats in the old town harbour at sunset

Croatia, Dubrovnik, view of the old town rooftops

Croatia, Dubrovnik, Aerail view of Dubrovnik

Croatia, Dubrovnik, view of the old town at dusk

Old Barn in Autumn, Wenatchee National Forest, Washington, USA

City walls. Ark fortress, Bukhara, a UNESCO World Heritage Site. Uzbekistan

The main gate to the Khuna Ark citadel and the Kalta Minor minaret. Old town of Khiva (Itchan Kala), a Unesco World Heritage Site. Uzbekistan

Ota Darvoza, the western gate to the old town of Khiva, at dusk. In the right side, the Mohammed Amin Khan madrasah and the Kalta Minor minaret. A UNESCO World Heritage Site, Uzbekistan

The old town of Khiva (Itchan Kala), a Unesco World Heritage Site, seen from the Khuna Ark citadel. Uzbekistan

Morocco, Marrakech-Safi (Marrakesh-Tensift-El Haouz) region, Marrakesh. A man wearing a djellaba walks past a decorative doorway in the medina (old town).

Public Footpath Sign & Gate, Lake District National Park, Cumbria, England

Croatia, Dalmatia, Dubrovnik, Old town, Sunset over the city walls and harbour

Croatia, Dalmatia, Dubrovnik, Old town, view of the old town at sunset

England, Calderdale. A winter sunrise in West Yorkshire.

Pale di San Martino range, overlooking the San Lucano valley, Taibon Agordino, Belluno Province, Veneto, Italy.

Obidos at dusk, one of the most beautiful medieval villages in Portugal, taken to the moors in the 12th century.

Spain, Andalusia, Cordoba. Calleja de las flores (street of the flowers) in the old town

Spain, Castile and Leon, Avila. Fortified walls around the old city

Spain, Castilla and Leon, Avila, old city listed as World Heritage by UNESCO, the ramparts dated 12th century

The Great Wall at Mutianyu nr Beijing in Hebei Province, China

The Great Wall at Mutianyu nr Beijing in Hebei Province, China

The Great Wall at Mutianyu nr Beijing in Hebei Province, China

Great Wall; Jinshanling; Beijing; China

View at dusk of Vila Vella, the medieval old town of Tossa del Mar, Costa Brava, Catalonia, Spain

Fishing boat on the beach with medieval town walls in the background, Tossa del Mar, Costa Brava, Catalonia, Spain