In the late 1960s and early 1970s, a handful of artists began leaving New York City to make monumental artworks in the landscape of the American Southwest. Frustrated by the commodity driven structures of museums and galleries and eager to explore new forms of sculpture and drawing, artists like Robert Smithson, Walter De Maria, and Michael Heizer picked up bulldozers and shovels and began to make work from the land. Smithson, for example built Spiral Jetty: a spiraling pathway of stone situated in The Great Salt Lake. Walter DeMaria constructed a grid of steel lightening rods called The Lightning Field in a remote section of the New Mexico Desert. A piece called Double Negative by Michael Heizer resembles a monumental excavation, carved from a mesa in Nevada. These pieces, and many others like them, are known as Land art, and they’re the subject of a fascinating new documentary by director James Crump.