Art Deco flourished after WWI, during an optimistic period known as the roaring twenties. Art Deco made its first appearance Paris's Exposition Internationale des Arts Decoratifs et Industriels Modernes in 1925. The new design turned modernism into a kind of fashion, used mostly for architectural and decorative arts. The style was very geometric and simple. Artists mainly focused on color and line in their designs, using nationalism and machinery as their inspiration. The effect of these pieces was striking and powerful, which by the mid 1930's reminded the victims of the Great Depression in 1929 of the bright, hope-filled future that never came after the war. Therefore, people began to associate it with extravagance and pompousness, and by WWII in 1939, people were done with the Art Deco style.