The works of Piet Mondrian and Richard Serra are profoundly related to the metropolis. Their works embrace different urban temporalities elapsed in the twentieth century. They were directly and indirectly influenced by music and dance, temporal arts equally confined to the urban phenomenon. Mondrian identifies the universal balance premises of his neoplastic theory in the modern, dynamic and fast Parisian environment of the first half of the twentieth century. He tries to accomplish his theory in other arts besides painting, so that by integrating art in life, the former would disappear. His arrival in America coincides with the artistic world center move from Paris to New York. In the cultural clash between Europe and America, one realizes the differences between the New World`s monumental scale and its dynamic people, against the shy dimensions and contemplative nature of the men in the Old Continent. The metropolis` mechanization is no longer polemic or fascinating, but responsible for the monotonous and repetitive urban life, from which the Post-Minimalists emerged, among them Serra. The utopian character of Mondrian`s painting, whose virtuality intended to transform reality, like America`s ripe society example, is absent in post-war art. The planes inserted by Serra in the urban fabric don`t intend to succumb to the cubist grid`s collapse. They seek the literal clash between the metropolis citizen and what surrounds him, in a very little tangible world.