John walked the broken rim for more than an hour, pulling his helmet's binocular lenses down over his faceplate for long periods of time, taking in as much as he could of the greatest canyon on Mars, feeling the euphoria of red land. He threw rocks over the side and watched them disappear, he talked to himself and sang, he hopped on his toes in a clumsy dance. Then he got back in his rover, refreshed, and drove a short distance along the rim, to the start of the cliff road.