This term for a modern style in architecture was coined in 1932 when Henry-Russell Hitchcock and Philip Johnson presented an exhibition of contemporary European architecture at the Museum of Modern Art in New York. Hitchcock and Johnson identified three key design principles: architecture as volume rather than mass, regularity rather than symmetry in the façade, and the rejection of applied ornament. Hallmarks of the International Style include ribbon windows, curtain walls and the use of modern materials (steel, concrete and glass). Important early practictioners were Ludwig Mies van der Rohe, Marcel Breuer and Le Corbusier.