"Spider" Dan Goodwin, the 50-something climber also called the "skyscraper man," scaled San Francisco's 58-story Millennium Tower on Monday, taking about three hours to get to the top, where he was arrested. Why was he climbing, exactly?

"To raise awareness about the vulnerability of buildings to terrorism," apparently! So: Now you are aware, that buildings are vulnerable to terrorism. Something else that raised awareness of buildings' vulnerability to terrorism: 9/11. And another thing that helped raise my awareness that buildings are vulnerable to terrorism: Looking at buildings.

Goodwin also apparently climbs buildings to let the world know that he is a cancer survivor. He used "suction cup-like devices" to get to the top, pausing to drink water given to him by residents of the tower.