HGP809202: West Front and Spire, Norwich Cathedral, Norfolk (photo) / Bridgeman Images

SAP492262: Portal of Mary, West Facade, Cologne Cathedral, Germany, 2010 (photo) / Bridgeman Images

SAP478970: Facade of the Convent of the Knights of Christ, Tomar, Portugal, 2009 (photo) / Bridgeman Images

HGP362651: Chichester Cathedral and Bishop's Palace Gardens, West Sussex (photo) / Bridgeman Images

EHT369389: Aerial view of Belsay Castle and Gardens (w/c on paper), Ball, Terry (20th Century) / Bridgeman Images

DGA539293: Italy, Molise region, Termoli, Castle of Termoli / Bridgeman Images

DGA542285: Portugal, Leiria, Leiria castle, (14th century) / Bridgeman Images

DGA542831: Portugal, Beja castle, (13th century) / Bridgeman Images

HGP424900: Aberdour Castle (photo) / Bridgeman Images

UIG1566149: St. Theodor (Iron Gate), Split, Split-Dalmatia, Croatia (photo) / Bridgeman Images

XIR1631464: Chateau de Montaigne, Dordogne (engraving), French School, (19th century) / Bridgeman Images

UIG1565023: Church of St. Nedelya, Sofia, Bulgaria (photo) / Bridgeman Images

TW1213608: The Black Gate, Newcastle (w/c (wash) on paper), Ridley, John (19th century) / Bridgeman Images

UIG1566695: Astronomical Clock and Calendar of the Old Town Hall, Prague, Czech Republic (photo) / Bridgeman Images

UIG2918758: Mont-Saint-Michel And Mudflats In The Bay At Dusk (photo) / Bridgeman Images

TRK2922112: Capital depicting a siren-fish with double tail, West gallery, 12th century, Cloister of Sant Pere de Galligants Abbey, Girona, Spain (photo) / Bridgeman Images

DPS3255039: Blarney castle; County Cork, Ireland (photo) / Bridgeman Images

DPS3256139: Dublin, Co Dublin, Ireland; Street Scenes With Christ Church Cathedral In The Background (photo) / Bridgeman Images

HGP2629373: Residential buildings and ditches at Helmsley Castle, Yorkshire (photo) / Bridgeman Images

HGP2629361: The Norman Keep through an arch, Rising Castle, Norfolk (photo) / Bridgeman Images

DGA2573119: Turaida castle (1214), near Sigulda, Latvia / Bridgeman Images

DGA2573107: Jaunpils castle, founded in 1301 by Livonian Order, Jaunpils, Latvia / Bridgeman Images

GRL6166262: The Cloister of the Benedectine monastery (XII century): a series of capitales on the Eastern side of the cloister (photo) / Bridgeman Images

DGA5651847: Walls of Radicofani Fortress, Val d'Orcia Park of Art, Nature and Culture (UNESCO World Heritage List, 2004), Tuscany, Italy, 10th-13th century / Bridgeman Images

DPS3503702: Bantry House And Gardens, Co Cork, Ireland; The Italian Garden During Summer (photo) / Bridgeman Images

MPX5159108: Caerphilly Castle, a medieval fortification in Caerphilly in South Wales. 6th October 1969 (b/w photo) / Bridgeman Images

CPH183800: Six-winged seraphim, from the pendentive of the Genesis Cupola in the atrium (mosaic) (detail), Veneto-Byzantine School / Bridgeman Images

MEP943606: King William II offering to the Virgin the temple of Monreale, 1180, 12th Century, mosaic / Bridgeman Images

DGA912309: Cathedral of Notre-Dame (13th century) (UNESCO World Heritage Site, 1991), Reims, Champagne-Ardenne, France / Bridgeman Images

DGA914148: Female figures, fresco in courtyard of Visconti Castle (13th century), Locarno, Ticino, Switzerland / Bridgeman Images

DGA914177: View of St Sophia Cathedral (1045-1050), Kremlin Palace (Unesco World Heritage List, 1992), Veliky Novgorod, Northwestern District, Russia / Bridgeman Images

DGA910854: The Cattolica, 9th-10th century Byzantine Church, Stilo, Calabria, Italy Detail of cupola / Bridgeman Images

DGA910171: Facade of apse, detail from Cathedral of Assumption of Mary and Saint Canius (11th-13th century), Acerenza, Basilicata, Italy / Bridgeman Images

DGA572371: Syria, Aleppo, Royal Palace baths in Citadel / Bridgeman Images

DGA646481: Spain, Castile-La Mancha, View of Guadamur Castle / Bridgeman Images

DGA646484: Spain, Castile-La Mancha, View of Guadamur Castle / Bridgeman Images