Rippling sand dunes, icy cliffs spied near Mars' north pole (photos)

Photo from mars orbit, showing rippling sand dunes to the left and some patches of water ice to the right.

The Martian north polar region is a strange and fascinating place, even by the standards of its strange and fascinating planet. 

There, the dust that coats the surface of Mars mixes with water ice. Layers upon layers of dust and ice stack miles deep, covering a region the size of France.