Modern Architecture style was increased rapidly after World War I; it was based on the rational use of modern materials and the principles of functionalist planning, and the rejection of historical precedent and ornament. In mid 19th century there had been repeated attempts to assimilate modern technology in practice and theory and to formulate a modern style of architecture suitable to its age. A functionalist approach ultimately replaced the formerly eclectic approach to design. Technical progress in the use of iron and glass made possible the construction of Crystal Palace in London (1851), in which a remarkable delicacy was achieved. After that iron, steel, and glass enabled architects and engineers to enclose the vast interior spaces of train sheds, department stores, and market halls, but often the structural forms were clothed with irrelevant ornament. In 1889 the world famous was opened it was built completely with iron and in Chicago; William Le Baron Jenny pioneered the use of a complete steel skeleton for the urban skyscraper in his Home Insurance Building. As a result of these advances, the formal conception of architecture was also undergoing a reflective transformation. Frank Lloyd Wright, a pupil of Sullivan, experimented with the interpenetration of interior and exterior spaces in his residential designs. In Holland, where Wright’s work was widely admired, the architects of de Stijl sought to organize building elements into new combinations of overlapping and hovering rectangular planes.