The Algodones Sand Dunes or dune sea are the largest mass of sand dunes in California. This dune system or Erg extends for more than 40 miles (60 km) along the eastern edge of the Imperial Valley, just north of the border between the U.S. and Mexico. Some sections are wilderness areas, but the section closest to the border is an area where people can drive all-terrain vehicles and ride off road motorcycles leaving tyre tracks in the sand. In the early morning the rising sun creates deep shadows.
