had no idea what. >> rock crawlers can conquer just about any obstacle in their way. bob standich has been driving these vehicles for more than six years. >> driving a rock crawler is an adrenaline rush. i know a lot of guys get it from speed but believe it or not, crawling around sitting 50 feet up on the side of a hill, and you can feel the tires inching off of a rock underneath you, it's a pretty good rush. >> on july 7th, 2005, in portland, indiana, bob competes in a rock crawler tournament. fans pack in to cheer on these vehicles that look like something straight out of "mad max." >> some people watch for the races. some people watch for the wrecks. you got people there to watch rock crawling. you got people who can't wait to see what happens if one's going to fall off rock, and they do. >> the competition is fierce. the custom built rock crawlers can be dangerous. >> in essence you're trying to defy gravity to some extent.