ave engulfed 275 square

miles of desert here and created the largest gypsum dune field in the world. The dunes, brilliant and white, are ever changing. They grow, crest, then slump but always advance. Slowly but relentlessly the sand, driven by strong southwest winds, covers everything in its path. Within the extremely harsh environment of the dune field, even plants and animals adapted to desert conditions struggle to survive. Only a few species