Crenellated tower, XIII c., Torre di Palme, Fermo, Ascoli Piceno, Marche, Italy

Tower of Mangana (Torre Mangana), on site of Moorish city, Cuenca, Castille La Mancha, Spain, Europe

Basilica of Notre-Dame de Fourviere with its four crenellated octagonal towers, Lyon, France, Europe

Palazzo Vecchio, Piazza della Signoria, Florence (Firenze), UNESCO World Heritage Site, Tuscany, Italy, Europe

Amar Singh Gate of Agra Fort, 17th Century residence of Great Mughals and Mughal fort in Agra, Northern India

The Church of St Mary the Virgin and graveyard in Harefield, Middlesex, UK

Outer walls of the Ark Fortress, Registan Square, Bukhara, Uzbekistan

The Great Wall on the ridge tops above Mutinanyu, China.

Classic Chinese architecture in the tiled roof of a building in Mutianyu, China.

Classic Chinese architecture in the tiled roof of a building in Mutianyu, China.

Castle Castell de Capdepera, castellated battlement, Capdepera, Balearic Islands, Majorca

Italy, Veneto, Venice, Centro Storico, Arsenale, Part view of crenellated tower flying Italian tricolour flag with statue of Neptune in foreground against clear blue sky of late summer

Egypt, Alexandria, Citadel of Qaitbay, also known as Fort of Qaitbay.

Tower of Mamure Castle in Anamur, Mersin Province, Turkey

Tower of Mamure Castle in Anamur, Mersin Province, Turkey

Entrance of Mamure Castle in Anamur, Mersin Province, Turkey