Lightly marked trails are primarily made up of volcano cinder, which feels a bit like sand, but is actually made up of tiny lava pebbles that are much quicker to do damage. Expect a few small and large jumps and a ton of berms, and keep an eye out for the Hundred Dollar Bill, a nasty 90-foot hill climb, and the Sunset Crater, a 500-foot deep volcanic crater used by the Apollo astronauts for Lunar Rover practice.