Why must art be static? You look at an abstraction, sculptured or painted, an entirely exciting arrangement of planes, spheres, nuclei, entirely without meaning. It would be perfect but it is always still. The next step in sculpture is motion.

— Alexander Calder (1898–1976)

The American artist Alexander Calder is most famous for his work in mobile sculpture, a discipline he invented. He also worked in wire, motorized, and monumental sculpture and oil paint, among other forms.

The Calder Foundation has the widest repository on the Internet of images of his work.

The National Gallery of Art has a QuickTime VR tour of their 1998 Calder exhibit including videos of some of the exhibit’s moving sculptures.