Robert Smithson (January 2, 1938 – July 20, 1973) was an American artist known for sculpture and land art who often used drawing and photography in relation to the spatial arts. His work has been internationally exhibited in galleries and museums and is held in public collections including the Museum of Modern Art, New York, the Smithsonian American Art Museum, Solomon R. Guggenheim Museum, New York, the Tate Modern, London, the Whitney Museum of American Art, New York, among others. He was one of the founders of the Land Art movement whose best known work is the Spiral Jetty.