International Style
Around 1920, with the coming of the World Wars, architects found them selves in a difficult position. Before then, they had only had to design public buildings or buildings that needed to look nice etc. (Gothic cathedrals are a good example of this.) Suddenly, their was a need for buildings that were used for very specific purposes. The architects of the time found hidden talents they didn't know of, like that they knew all along how to design a school or a factory. Buildings were now being designed by how productive it would be rather than if it would make a nice postcard. Structures that followed street patterns or were asymmetrical started springing up everywhere.
Another innovation of this era was the use of steel. Before this, all buildings were load-bearing. That means that all of the weight of the building is supported by the walls, so the taller the building, the thicker the walls were at the bottom. With steel, they didn't have to do that anymore. If you had lived then, and you saw a building with a huge piece of glass on the ground level (Like window shopping displays), you would think something mighty strange was going on, because you would be used to seeing only small windows this close to the ground since all buildings had to be supported by their walls, didn't they? Well, no. Steel allowed designers and builders to make a frame, and then hang the walls from it. That's how they made skyscrapers. Many of the worlds first skyscrapers were built in Chicago, which was kind of like the International Style home for architects.
