During the Pleistocene Era, 26,000-10,000 years ago, the broad valley was formed by Lake Bonneville. When the lake waters subsided, human beings moved from the shoreline at the edge of the mountain slopes onto the valley floor. For 10,000 years, people have used this valley floor for habitation, hunting, trails, and utility corridors. Early peoples used the valley and surrounding mountains for the resources they needed to survive, developing trails to obtain water and to reach ceremonial areas, habitation sites, and places for gathering food, minerals, clay, plant materials, and rocks. In the 1700s, the Spanish traveled through the valley bottom, transporting supplies, slaves, and horses to the missions in what is now Southern California, using trails already on the landscape. Beginning in the 1800s, immigrant wagon trains heading to the gold fields and Spanish missions of California also traveled these existing routes. One group led by Jefferson Hunt and Captain Smith broke apart a few miles east of here; Hunt's group followed the existing road to the south, the California Overland Trail/Spanish Trail, and arrived three months earlier than Smith's group, which turned west and eventually reached the place in central California that survivors identified as Death Valley. The trail along the lower slopes and valley floor to the north and south has been identified as the Old Spanish National Historic Trail. People still use this area for habitation, hunting, ranching, farming, and sight-seeing, and because these activities need electricity, the edge of the valley to the east was designated as a corridor for transmission lines and other utilities. Today, five power lines and three large gas pipelines run through the corridor, following the same routes that have been in place for 10,000 years.