Alexander Calder was an American sculptor who is best known for his innovative mobiles (kinetic sculptures powered by motors or air currents) that embrace chance in their aesthetic and his monumental public sculptures. Born into a family of artists, Calder's work first gained attention in Paris in the 1920s and was soon championed by the Museum of Modern Art in New York, resulting in a retrospective exhibition in 1943. Major retrospectives were also held at the Solomon R. Guggenheim Museum (1964) and the Museum of Contemporary Art, Chicago (1974). [Wikipedia]