Lava plains cover Elysium Planitia, burying evidence of its older geologic past. Among the buried evidence is the source of the flood channel called Marte Vallis, which extends about 620 miles across the Elysium plain and 60-odd miles wide. Marte Vallis is an important flood channel in part because it's so big, and in part because it's so young, especially compared to other flood channels that are more well-studied. Understanding Marte Vallis will help scientists understand Mars' recent hydrologic history, which is especially important because when this flood channel was carved, the planet was cold and dry. But to study it, scientists have to peel back the lava layers.