For the past month, NASA's Curiosity rover has been shadowing Gediz Vallis, a channel that scientists think may be the fossil of an ancient Martian river.
Last week, Curiosity reached the north side of Pinnacle Ridge, part of a rock wall that looms over Gediz Vallis. In fact, after Curiosity navigated bumpy ground to do that, it found that the ridge's south side is navigable.
