Modern architecture, or modernist architecture, was an architectural movement or architectural style based upon new and innovative technologies of construction, particularly the use of glass, steel, and reinforced concrete; the idea that form should follow function (functionalism); an embrace of minimalism; and a rejection of ornament. It emerged in the first half of the 20th century and became dominant after World War II until the 1980s, when it was gradually replaced as the principal style for institutional and corporate buildings by postmodern architecture. According to Le Corbusier the roots of the mouvement were to be found in the works of Eugène Viollet le duc. Origins Modern architecture emerged at the end of the 19th century from revolutions in technology, engineering, and building materials, and from a desire to break away from historical architectural styles and to invent something that was purely functional and new. The revolution in materials came first, with the use of cast iron, drywall, plate glass, and reinforced concrete, to build structures that were stronger, lighter, and taller. The cast plate glass process was invented in 1848, allowing the manufacture of very large windows. The Crystal Palace by Joseph Paxton at the Great Exhibition of 1851 was an early example of iron and plate glass construction, followed in 1864 by the first glass and metal curtain wall. These developments together led to the first steel-framed skyscraper, the ten-story Home Insurance Building in Chicago, built in 1884 by William Le Baron Jenney and based on the works of Viollet le Duc. French industrialist François Coignet was the first to use iron-reinforced concrete, that is, concrete strengthened with iron bars, as a technique for constructing buildings. In 1853 Coagent built the first iron reinforced concrete structure, a four-story house in the suburbs of Paris. A further important step forward was the invention of the safety elevator by Elisha Otis, first demonstrated at the New York Crystal Palace exposition in 1854, which made tall office and apartment buildings practical. Another important technology for the new architecture was electric light, which greatly reduced the inherent danger of fires caused by gas in the 19th century. The debut of new materials and techniques inspired architects to break away from the neoclassical and eclectic models that dominated European and American architecture in the late 19th century, most notably eclecticism, Victorian and Edwardian architecture, and the Beaux-Arts architectural style. This break with the past