The Stock Market Crash of 1929 served as the Great Divide between the '20s and the '30s, and between European and American Art Deco designs. The distinct moods of the two decades dramatically affected the arts of each. The '20s, characterized by voluptuous interiors, curvilinear forms, exotic materials and outlandish designs gave way in the '30s (generally referred to as the Art Moderne phase) to rectilinear forms, sleek streamlined finishes, synthetic materials and an infatuation with speed, dynamism and futuristic Buck Rogers elements. In America, the step-back skyscraper, the rich interiors of Donald Deskey and the modern-age, mass-produced vision of Kem Weber, Norman Bel Geddes and Walter Dorwin Teague pushed design into the realm of tomorrow. Over a 70-year period, Modernism's motivating spirit passed from reactionary to visionary.