Alexander Calder (b. 1898, Lawnton, Pennsylvania; d. 1976, New York) is one of the most acclaimed and influential sculptors of the twentieth century. He is renowned for the invention of the mobile, a kinetic construction of suspended abstract elements that describe individual movements, moving and balancing in changing harmony. Calder also devoted himself to making outdoor sculpture on a grand scale from bolted sheets of steel, many of which stand in public plazas in cities throughout the world. Pace Gallery has worked closely with the Calder estate since 1984.