Spines

A piece of Mars: Here are some old dunes that look a little like vertebrae of fossils (if you think they look like dragon spines poking out of the ground then you’re playing too many video games). The white areas are stabilized and possibly lithified. The blue areas are where the dunes are being actively eroding, exposing old bedding (faint parallel stripes) within the dunes. (HiRISE ESP_030583_1610, NASA/JPL/University of Arizona)