Wind-blown sand is a highly effective agent of abrasion, as anyone who has been in a sandstorm will agree. Wind is one of the few agents that can and does carry material uphill. Here, the wind carries sand for miles before piling it up into this huge dune. Perhaps the most popular spot in the park, Blow Sand Hill is illuminated by a circle of headlights on many weekend nights.

Click here to view a video of Ocotillo Wells.