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 ...

Mars has always captured human imagination with its striking red hues and mysterious landscapes. Recent images from NASA’s ...

So we drove out into the middle of the broad stony basin until we found a 50-foot-tall barchan to give us some shelter for the night. We awoke before dawn. The wind on the dune crest had died down ...