Where on Earth? - May 2010

Clues for May 2010:
1. This sand is made of the mineral gypsum. The gypsum was first deposited here about 250 million years ago. Ten million years ago, part of a dome containing the gypsum deposit started to collapse, forming a basin. The basin was then filled in with gypsum eroded from the  surrounding edges of the deposit.
2. The sand is part of a dune field that covers more than 700 square kilometers — the largest gypsum dune field in the world. Few gypsum dune fields exist because gypsum is soluble in water and is normally carried away by rivers, but no rivers leave the basin that hosts these dune fields.
3.This park was formally recognized in 1933, though attempts to make it a national park began as early as 1898. More than half a million people visit the park each year.
Name this valley and its location.
Scroll down for the answer
Answer: This 700-square-kilometer gypsum dune field is White Sands National Monument in New Mexico. The park became a national monument in 1933 after several previous failed attempts. Photo is by Brian Haines.
May winners
Joy Crisp (La Canada, Calif.)
Chris Drabandt (Sacramento, Calif.)
James H. Elison (Bakersfield, Calif.)
Barbara Gauthier-Warinner (Interlochen, Mich.)
Jim Hensel (Tonawanda, N.Y.)
Marilyn Hurst (Madison, Wis.)
William Lund (Cedar City, Utah)
John Murray (Winnipeg, Alberta)
Chris Scott (Brentwood, Tenn.)
Victoria Sieglen (Wichita, Kan.)

To submit your photographs to our Where on Earth? contest, send them via e-mail to

23 May 2010