Europe has an architectural tradition that is at least as old as the Minoan Palace of Knossos on Crete, which was built over the centuries between 2000 and 1300 BCE, and if one defines Stonehenge as architecture, the tradition is a thousand years older. Today, European architecture is exemplified by Remment Lucas Koolhaas, the Dutch architect whose China Cable Television building in Beijing has already been hailed as a masterpiece. Yet European architecture is enormously diverse. The Palace of Versailles and the fortresses of Sebastian Le Prestre de Vauban are both French masterpieces of the same era that are profoundly different buildings: symmetry is perhaps their only similarity. Likewise, Russian architecture encompasses the colorful and ornate Orthodox Russian Cathedral of St. Basil's in Moscow's Kremlin fortress, the massive Italianate grace of the Hermitage in Petersburg and the "Stalinist Wedding Cake" style of Soviet architecture.
Two of the main themes of European architecture have been secular power and religious faith and most of the remaining examples of pre-modern European architecture are either castles or churches. Neither early castles nor early churches are graceful or elegant. Churches, as well as castles, sheltered peasants from the raids and invasions that were a feature of Europe after the collapse of the Roman Empire in the West in 476 CE. These were relatively simple buildings, usually of stone, and strongly built to withstand armed attack.
As Europe became more Christian and more settled, architecture became more refined and ornate. A major cause of this refinement was the Crusades into the Holy Land of the 11th, 12th and 13th centuries, meant to liberate Jerusalem from the Muslims and relieve pressure on the Byzantine Empire from Muslim Turks. The European need to supply large armies far from home reopened and reinvigorated long-dormant trade routes, while the Crusaders who survived brought back a taste for Middle Eastern and Asian goods, from spices to textiles, glass to crude gunpowder. The second impetus to the development of architecture was the Renaissance, the resurgence of classical art, science and learning, combined with exposure to Arab work in those fields that transformed European art and culture from the 14th to the 17th centuries.
The castles of the nobility were used as both homes, with public functions and administrative facilities, and a base (including barracks) for military operations against other nobles or to suppress peasant uprisings. Churches, particularly masterpieces such as the cathedrals at Chartres, Cologne and Reims, would likewise dominate areas, often for miles around, in a statement of the wealth and power of the (Catholic) church. But these massive, ostentatiously beautiful buildings were also how many craftsmen expressed themselves creatively in a time when the common man had almost no outlet for individual self-expression. The piety of these craftsmen was often real; beauty and skill were not just a way to earn their bread, but an offertory to God.
The Industrial Revolution, spanning the 18th and 19th centuries, changed the living standards of ordinary people in ways that went far beyond access to more food and better clothing. The Industrial Revolution made mass-produced copies of extremely skilled craftwork widely available to a growing middle class. A pent-up hunger for decoration in the Victorian era, late 19th to early 20th century, led to such lavish over-decoration that it gave rise to the (only relatively) simplified aesthetic of the Arts and Crafts Movement, exemplified by the dictum of English designer William Morris: "Have nothing in your homes that you do not know to be useful and believe to be beautiful."
European architecture was further simplified in reaction to the massive destruction of housing stock in two world wars, especially in the Soviet Union, where wanton German destruction had reduced people to living in dugouts. However, much of the coldness and hardness of early modern architecture was also an emotional response by the living to the utter failure of European civilization between 1914 and 1945. In 1923, when the architect Le Corbusier spoke of a house being a machine in which to live, he spoke as a Frenchman who had seen his young countrymen slaughtered at places like Verdun and knew they would have to do it again, in a second World War.
Today's modern architecture, while less grim and often vibrantly experimental in its use of angles and materials, often dispenses with the balanced harmony and symmetry that has been such a hallmark of European architecture. Koolhaas, who is perhaps the most influential architect working today, is particularly known for the asymmetry of his buildings.