The International Style or internationalism is a major architectural style that was developed in the 1920s and 1930s and was closely related to modernism and modernist architecture. It was first defined by Museum of Modern Art curators Henry-Russell Hitchcock and Philip Johnson in 1932, based on works of architecture from the 1920s. The terms rationalist architecture and modern movement are often used interchangeably with International Style, although the former is mostly used in the English-speaking world to specifically refer to the Italian rationalism, or even the International Style that developed in Europe as a whole. It is defined by the Getty Research Institute as "the style of architecture that emerged in Holland, France, and Germany after World War I and spread throughout the world, becoming the dominant architectural style until the 1970s. The style is characterized by an emphasis on volume over mass, the use of lightweight, mass-produced, industrial materials, rejection of all ornament and colour, repetitive modular forms, and the use of flat surfaces, typically alternating with areas of glass." Background Around the start of the 20th century, a number of architects around the world began developing new architectural solutions to integrate traditional precedents with new social demands and technological possibilities. The work of Victor Horta and Henry van de Velde in Brussels, Antoni Gaudí in Barcelona, Otto Wagner in Vienna and Charles Rennie Mackintosh in Glasgow, among many others, can be seen as a common struggle between old and new. These architects were not considered part of the International Style because they practiced in an "individualistic manner" and seen as the last representatives of Romanticism. The International Style can be traced to buildings designed by a small group of modernists, the major figures of which include Ludwig Mies van der Rohe, Jacobus Oud, Le Corbusier, Richard Neutra and Philip Johnson. The founder of the Bauhaus school, Walter Gropius, along with prominent Bauhaus instructor, Ludwig Mies van der Rohe, became known for steel frame structures employing glass curtain walls. One of the world's earliest modern buildings where this can be seen is a shoe factory designed by Gropius in 1911 in Alfeld, Germany, called the Fagus Works building. The first building, built entirely on Bauhaus design principles, was the concrete and steel Haus am Horn, built in 1923 in Weimar, Germany, designed by Georg Muche. The Gropius designed Bauhaus school building in Dessau, built 1925–26 and the Harvard Graduate