By 1920 there was an increasingly wide understanding that building forms must be determined by their functions and materials if they were to achieve intrinsic significance or beauty in contemporary terms, without resorting to traditional ornament. Instead of viewing a building as a heavy mass made of ponderous materials, the leading innovators of modern architecture considered it as a volume of space enclosed by light, thin curtain walls and resting on slender piers. The visual aesthetic of modern architecture was largely inspired by the machine and by abstract painting and sculpture.
In giving form and coherence to modern architecture, Le Corbusier's book Vers une architecture (1923, tr. 1927) played an important role, as did the writings of the Dutch architect J. J. P. Oud and the German architect Walter Gropius, who also headed the Bauhaus in Dessau. Other early leaders of the modern movement included Ludwig Mies van der Rohe, Marcel Breuer, and Ernst May in Germany and Raymond Hood, Albert Kahn, Richard J. Neutra, William Lescaze, and George Howe in the United States.
In 1932 the label "International style" was applied to modern architecture by the Museum of Modern Art, New York City, anticipating its growing acceptance around the world. The United States became a stronghold of modern architecture after the emigration of Gropius, Mies, and Breuer from Germany during the 1930s. By the mid-20th cent. modern architecture had become an effective instrument for dealing with the increasingly complex building needs of a global society. Large architectural firms such as Harrison and Abramovitz and Skidmore, Owings, and Merrill did much to popularize modern architecture around the world after World War II.
At the same time new technological developments continued to influence architects' designs, particularly in the realm of prefabricated construction, as seen in the works of R. Buckminster Fuller and Moshe Safdie. The development of sophisticated air conditioning and heating systems also allowed modern architecture to spread from the temperate climates of Europe and North America to countries with extremely varied weather conditions.