What petrified sand dunes look like on Mars
 

If you're the outdoorsy type, you might have already seen petrified sand dunes in person (in Utah, for instance) -- the photo above, however, isn't of a desert here on Earth. It's an image stitched together using several shots captured on August 27...

http://www.engadget.com/2015/09/12/p...&ncid=rss_semi