In a land of stark white sand, a little fall color really stands out. White Sands National Monument in New Mexico preserves part the world’s largest gypsum dunefield. Gypsum sand is considered rare because gypsum is water soluble – it dissolves in water like sugar in iced tea. The 275-square miles of dunes are comprised of over 4.5 billion tons of gypsum sand. It is one of the many things that make White Sands a unique and special place. Photo by Jim Langford (www.sharetheexperience.org).