The document discusses the International Style of Architecture, which developed in the 1920s-1930s and emphasized modern materials like steel, glass, and concrete. It expresses structure directly and eliminates ornamentation. Key characteristics included rectilinear forms, exposed structures, rejection of color and ornament, and open interior spaces. Design principles involved symmetry, asymmetry, repetition, and rhythm. Prominent architects who helped define the style included Walter Gropius, J.J.P. Oud, and Le Corbusier. By the 1970s, the style had become so dominant that it stifled innovation.