Wright, generally acknowledged as one of the greatest architects of the 20th cent., developed a highly original approach to residential design before World War I, which became known as the "Prairie Style." His early work, executed in and around Chicago, combined open planning principles with horizontal emphasis, asymmetrical facade elevations, and broad, sheltering roofs, as seen, for example, in his Robie House (1909). Wright, who stood apart from the European-derived modernist mainstream, continued to design buildings into his old age, producing some of his finest and most idiosyncratic works, such as the Guggenheim Museum in New York City (1946–59).
The unornamented, machine-inspired aesthetic of European modernism was introduced to the United States through such foreign-born architects as Richard Neutra, Rudolph Schindler, and William Lescaze during the 1920s. Later dubbed the International style, this functionalist mode of architecture became preeminent in the United States after World War II, particularly in the design of corporate office buildings. Notable examples include Skidmore, Owings and Merrill's Lever House (1952) and Ludwig Mies van der Rohe's Seagram Building (1956–58), both in New York City. With the immigration to the United States of such prominent Europeans as Walter Gropius and Mies, the curricula of many American architectural schools were revamped along the lines of the Bauhaus in Germany.
Around 1960 a formal and theoretical reaction to the International style began to take shape as architects became increasingly disenchanted with the sterile aestheticism of much postwar building. Louis I. Kahn reintroduced axial planning and other Beaux-Arts principles, while Eero Saarinen experimented with dynamic sculptural forms. In addition, Robert Venturi argued for the value of studying the vernacular and commercial landscape, thus broadening the theoretical foundations of modern design and ushering in the postmodern era. By the early 1980s postmodernism had become America's dominant style, particularly for public buildings. At around this time, the United States, often an importer and interpreter of modernist architectural trends, became an exporter of postmodernist concepts. In postmodern design, architects such as Philip Johnson (in one of his many changes of architectural style), Michael Graves, Richard Meier, Charles Gwathmey, Robert A. M. Stern, Charles Moore, Helmut Jahn, Thomas Beeby, and others recombined ornament, historicism, technology, and often vivid color in diverse, eclectic, and often witty manners. Among postmodernism's most notable buildings are Graves's Portland Building (1982), Portland, Oreg., and Johnson's AT&T Building, now the Sony Building (1978–84), New York City. While postmodern architecture remained a dominant mode in the 1990s, some contemporary architects have created their own styles. Foremost among these is Frank Gehry, whose asymmetrical, sculptural buildings using both common and unusual materials, are an architectural world unto themselves. One of his finest works is the monumental and organic titanium steel Guggenheim Museum, Bilbao, Spain (1997).