NASA's Curiosity rover is preparing for the next leg of its journey, a months-long trek to a formation called the boxwork, a set of weblike patterns on Mars's surface that stretches for miles. It will soon leave behind Gediz Vallis channel, an area wrapped in mystery. How the channel formed so late during a transition to a drier climate is one big question for the science team. Another mystery is the field of white sulfur stones the rover discovered over the summer.