A pivotal figure in the evolution of post-war sculpture, Robert Smithson created iconic Land art that radically changed prevailing ideas about the making and viewing of art. Working with unconventional materials including soil, rocks, disused industrial sites, and language, the artist explored the metaphorical qualities inherent in geological formations and the process of entropy. Smithson originated what he called non-sites, referring to the exhibition of materials that have been removed from their natural geological setting and displayed in a gallery space with documentation of their origins and extraction, such as photographs and maps. His best-known work remains Spiral Jetty (1970), a large basalt formation in the shape of a coil, extending out into the waters of Utah’s Great Salt Lake.