Area 51 the base extends further east. After leaving the restricted area, Groom Lake Road descends eastward to the floor of the Tikaboo Valley, passing the dirt-road entrances to several small ranches, before converging with State Route 375, the "Extraterrestrial Highway", south of Rachel. Area 51 shares a border with the Yucca Flat region of the Nevada Test Site, the location of 739 of the 928 nuclear tests conducted by the United States Department of Energy at NTS. The Yucca Mountain nuclear waste repository is southwest of Groom Lake. Groom Lake is a salt flat in Nevada used for runways of the
Area 51 over Area 51's actual operations. While the veterans deny the existence of a vast underground railroad system, many of Area 51's operations did (and presumably still do) occur underground. Several people have claimed knowledge of events supporting Area 51 conspiracy theories. These have included Bob Lazar, who claimed in 1989 that he had worked at Area 51's "Sector Four (S-4)", said to be located underground inside the Papoose Range near Papoose Lake. Lazar has stated he was contracted to work with alien spacecraft that the U.S. government had in its possession. Similarly, the 1996 documentary "Dreamland" directed by Bruce Burgess