Alexander Calder was an American sculptor whose radical invention of the mobile — a kinetic sculpture suspended in balance — transformed the possibilities of three-dimensional art. Born in Philadelphia into a family of artists, Calder trained as a mechanical engineer before turning to art, and that dual sensibility never left him.

His work moves between monumental stabiles anchoring public plazas and delicate mobiles that drift with the slightest breath of air. Calder brought wit, engineering precision, and an instinct for pure joy to everything he made — from circus wire figures to large-scale painted steel.