Expressionism architecture developed in early 20th century Europe as artists sought new ways to convey emotional and spiritual ideas through abstract and distorted forms. Key characteristics included biomorphic shapes inspired by nature, asymmetric designs, and use of new materials like concrete and glass. Prominent expressionist architects included Erich Mendelsohn, Fritz Höger, Peter Behrens, and Rudolf Steiner. Mendelsohn's Einstein Tower and Höger's Chilehaus used innovative brick designs to distort forms for emotional effect. Steiner's Goetheanums in Dornach fused architecture, sculpture, color and space to convey spiritual concepts of metamorphosis.