Spiral Jetty is an earthwork sculpture constructed in April 1970 that is considered to be the most important work of American sculptor Robert Smithson. Smithson documented the construction of the sculpture in a 32-minute color film also titled Spiral Jetty. Built on the northeastern shore of the Great Salt Lake near Rozel Point in Utah entirely of mud, salt crystals, and basalt rocks, Spiral Jetty forms a 1,500-foot-long, 15-foot-wide counterclockwise coil jutting from the shore of the lake.