Alain Robert climbs tall office buildings with his bare hands, no hooks, no suction cups, no ropes, etc. It seems like utter madness - "you slip, you die."
Also, he suffers from vertigo.
His site has pictures of his rock climbing and building climbing.
This is of course totally irrelevant to anything except my brain breaks at the level of concentration (or insanity) needed to climb the outside of 70 story buildings with your bare hands.