America's Tallest Building
For 25 years, the skyscraper formerly known as the Sears Tower kept a watchful eye over a bustling Chicago skyline as the unrivaled tallest building in the world. Completed in 1973 by Sears, Roebuck & Co., the 108-story structure lost its world title in 1998 to the Petronas Twin Towers in Malaysia, and it was renamed the Willis Tower in 2009 when a London-based insurance broker purchased the building's rights. Still, the massive structure remains famous for its superlative size and former name, and has thus attracted its fair share of crazies: in 1981, a man donning little more than a Spiderman suit and suction cups first scaled the entirety of the glass building's 1451-ft (442 m) exterior. And he certainly wasn't the last to attempt the feat.