Crawl into the cave and begin at a wide pocket far back in the roof (starting feet out is acceptable.) Aiming for the obvious tufa pinch on the headwall, navigate the complex maze of pockets to an undercling and sloper at the lip, then set feet and pull a difficult cross to the pinch. Bump right along more underclings; one more frequently heartbreaking throw gains the good holds at the lip. This complex and sustained line is super fun and understandably popular.
Main section of the Mars Roof, second problem from the left.
I recommend a few pads, the landing is mostly safe except for the awkward shelf under the start.