Moscow, Russia -- St Basil's Cathedral was built during the 16th century by Ivan IV or, as he was nicknamed, Ivan the Terrible. The structure's design and color was modified throughout its history.
Moscow, Russia -- St Basil's Cathedral was built during the 16th century by Ivan IV or, as he was nicknamed, Ivan the Terrible. The structure's design and color was modified throughout its history.
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Spain, Barcelona -- The Sagrada Família. Construction of the neo-Gothic basilica began in 1882 and remains unfinished to this day.
Spain, Barcelona -- The Sagrada Família. Construction of the neo-Gothic basilica began in 1882 and remains unfinished to this day.
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Milan, Italy -- The Milan Cathedral (Duomo di Milano) is one of the largest churches in Europe and took nearly six centuries to complete.
Milan, Italy -- The Milan Cathedral (Duomo di Milano) is one of the largest churches in Europe and took nearly six centuries to complete.
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London, United Kingdom -- St Paul's Cathedral was built during the 17th century. Its dome, famous to London's skyline, is comprised of an outer dome, a concealed brick cone for structural support and an inner dome.
London, United Kingdom -- St Paul's Cathedral was built during the 17th century. Its dome, famous to London's skyline, is comprised of an outer dome, a concealed brick cone for structural support and an inner dome.
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Paris, France -- The Notre Dame Cathedral is a treasure of French Gothic architecture. A devastating fire in 2019 caused its spire to collapse. Restoration efforts have been put on hold due to the pandemic.
Paris, France -- The Notre Dame Cathedral is a treasure of French Gothic architecture. A devastating fire in 2019 caused its spire to collapse. Restoration efforts have been put on hold due to the pandemic.
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The Vatican, Rome, Italy -- Saint Peter's Basilica is one of the world's most beloved landmarks. Its interior houses many masterpieces of Renaissance and Baroque art, notably Michelangelo's "Pietà" sculpture.
The Vatican, Rome, Italy -- Saint Peter's Basilica is one of the world's most beloved landmarks. Its interior houses many masterpieces of Renaissance and Baroque art, notably Michelangelo's "Pietà" sculpture.
ANDREAS SOLARO/AFP via Getty Images
Reykjavik, Iceland -- Hallgrímskirkja Cathedral is among the tallest structures in Iceland and took more than four decades to build. Its architect referenced Icelandic traditions and materials in his design, and part of the church's structure symbolizes the country's mountains and glaciers.
Reykjavik, Iceland -- Hallgrímskirkja Cathedral is among the tallest structures in Iceland and took more than four decades to build. Its architect referenced Icelandic traditions and materials in his design, and part of the church's structure symbolizes the country's mountains and glaciers.
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Metz, France -- The Metz Cathedral or Cathedral of Saint Stephen celebrates its 800th anniversary this year. Its nickname, "God's Lantern" is befitting both of the building's distinctive honey-like glow -- a property of the local limestone -- and an expanse of stained glass that is among the world's largest.
Metz, France -- The Metz Cathedral or Cathedral of Saint Stephen celebrates its 800th anniversary this year. Its nickname, "God's Lantern" is befitting both of the building's distinctive honey-like glow -- a property of the local limestone -- and an expanse of stained glass that is among the world's largest.
Jean-Christophe Verhaegen/AFP/Getty Images