If the prospect of riding a motorcycle didn't seem dangerous enough already, imagine doing it completely sideways on something called "The Wall of Death".
As one of the last remaining traditional families of traveling daredevil wall riders, that is exactly what the Ken Fox Troupe does in front of crowds all over Europe. Using only centrifugal force and the friction of their tires, Ken Fox and his troupe defy gravity and ride their motorcycles sideways up a vertical wall.
This excellent short film tells the interesting tale of how Fox and his family ended up riding "The Wall of Death".
Hat tip to _Engineer!