Chlorofluorocarbons or CFCs are a chemical compound containing carbon, chlorine, and fluorine. Throughout the 20th century, CFCs were mass produced for their popularity in refrigeration and spray cans. In the 1970s, evidence began to show the harmful effects of CFCs on Earth.
Originally created as Great Sand Dunes National Monument on March 17, 1932, Great Sand Dunes National Park and Preserve was established by an act of the United States Congress on September 13, 2004.
The largest dune is called Star Dune and is relatively stable and stationary because it is at a point where the various winds that shape the dunes converge. The depth of the sand at its crest is 130â140 feet (40â43 m) but this is small compared to other dunes in the area that have sand depths of up to 600â700 feet (180â210 m) deep. The primary source of the dune sands is probably the Cottonwood Mountains which lie to the north and northwest.