Related: See all the best images of Earth from space A group of five barchan, or "horned," sand dunes can be seen in a zoomed-in version of the 2013 photo (see below). Over time, these arrowhead ...

So we drove out into the middle of the broad stony basin until we found a 50-foot-tall barchan ... of a sand dune; the shady side usually has downdrafts, so you just drop like a stone. White ...