dirt biking on a cliffIf you think mountain climbing is gutsy, imagine dirt-biking along a narrow, rocky single track that just happens to be on the edge of an enormous cliff. One false move and you're stuck with the evil valley people for all eternity.

You'll get an adrenaline rush just from watching this devil-may-care helmet cam video. Luckily none of the riders plummeted to their deaths until, like, just after they switched the camera off.