In 1976, after three years of planning and multiple treks to the desert bordering Utah and Nevada, Nancy Holt finished what was to become her defining work. By this time, the sculptor and filmmaker had some well-received shows to her name; a famous, recently deceased husband whose career had largely overshadowed her own; and 40 acres of land in Utah’s Great Basin Desert.Sun Tunnels(1973–76) is composed of four massive cylindrical, concrete forms—large enough for a viewer to walk inside without ducking—positioned in a cross formation on the desert’s cracked clay floor. The project had been initiated shortly before Holt’s partner, Robert Smithson, died in a freak airplane crash in Texas. In the subsequent years, his widow spent countless secluded months in the Southwest, experimenting, scouting sites, and establishing her own personal relationship with the land. . .