For about 11,000 years, people in and around the San Luis Valley have used the dunes and the mountains behind them as landmarks for travel. Whether on foot, by horseback, Model A, or modern car, travelers have navigated by the dunes, the Crestone Needles, the San Juan Mountains on the western horizon, and passes through the Sangre de Cristo Mountains leading east. The Medano Pass Primitive Road and the Mosca Pass trail follow rough historic routes over the Sangre de Cristo Mountains.