Hans "No Way" Rey, former trials riding world champion and one of the pioneers of extreme mount biking, did this amazing biking stunt:
More recently, he did the unthinkable. As a publicity stunt, Hans rode down the vertical face of an Auckland high-rise. Utilizing a specially designed harness and braking system, Hans descended the 13 stories straight down.
Now, Hans run The Hans Rey Adventure Team, where bikes in exotic places: Link - Thanks Charles!