Fortified walls and towers of the Aljaferia palace dating from the 11th century, Saragossa (Zaragoza), Aragon, Spain, Europe

The 11th century Romanesque Cathedral, Domplatz, Speyer, Rhineland Palatinate, Germany, Europe

Fortified walls and towers of the Aljaferia Palace dating from the 11th century, Saragossa (Zaragoza), Aragon, Spain, Europe

Walls and towers at night of the Aljaferia Palace, dating from the 11th century, Saragossa (Zaragoza), Aragon, Spain, Europe

Fortified walls and towers of the Aljaferia palace dating from the 11th century, Saragossa (Zaragoza), Aragon, Spain, Europe

Fortified walls and towers of the Aljaferia palace dating from the 11th century, Saragossa (Zaragoza), Aragon, Spain, Europe

Fortified walls and towers of the Aljaferia palace dating from the 11th century, Saragossa (Zaragoza), Aragon, Spain, Europe

Fortified walls and towers of the Aljaferia palace dating from the 11th century, Saragossa (Zaragoza), Aragon, Spain, Europe

The Tower of London, 11th century medieval Norman castle that houses the Crown Jewels, UNESCO World Heritage Site, City of London, London, England, United Kingdom, Europe

The 11th century Lingaraja Temple complex dedicated to the Hindu deity Shiva in Bhubaneswar, nicknamed the City of Temples, Bhubaneswar, Odisha, India, Asia

The 11th century Rajarani Temple dedicated to the Hindu deity Shiva in Bhubaneswar, nicknamed City of Temples, Bhubaneswar, Odisha, India, Asia

The 11th Century Tower in Villa Rufolo Gardens, Ravello, Amalfi Coast, UNESCO World Heritage Site, Campania, Italy, Europe

Campanile and detail of the facade of the Basilica di San Marco, dating from the 11th century, Piazza San Marco, San Marco, Venice, UNESCO World Heritage Site, Veneto, Italy, Europe

Norwich cathedral, tower dating from 11th century, with 15th century spire, Norwich, Norfolk, England, United Kingdom, Europe

Burana Tower, an 11th century Karakhanid minaret, near Bishkek, Kyrgyzstan, Central Asia, Asia

Leaning Tower (Torre Pendente) dating from between the 12 and 14th centuries, and Duomo dating from the 11th century, Campo dei Miracoli, UNESCO World Heritage Site, Pisa, Tuscany, Italy, Europe

Stained glass window in the Cathedral of Our Lady, one of the world's oldest figurative stained glass windows, mid 11th Century, prophets window, Prophet Daniel, Augsburg Cathedral, Augsburg, Bavaria, Germany, Europe

Stained glass window in the Cathedral of Our Lady, one of the world's oldest figurative stained glass windows, mid 11th Century, prophets window, King David, Augsburg Cathedral, Augsburg, Bavaria, Germany, Europe

View through the balustrade to the roofs of Lausanne downtown. Tower on 11th century Cathedral Notre-Dame, Lausanne, Waadt, Switzerland

View through the balustrade to the roofs of Lausanne downtown. Tower on 11th century Cathedral Notre-Dame, Lausanne, Waadt, Switzerland

Night scene, west front, Romanesque Cathedral or Trani, 11th century, Trani, Bari, Apulia province, Italy, Europe

Burg Hiltpoltstein castle, 11th century, with Matthaeuskirche church in Winter, Hiltpoltstein, Upper Franconia, Bavaria, Germany, Europe