Not content with the regular views from its 103rd-floor Skydeck, the Sears Tower - which will soon be renamed the Willis Tower - is adding four enclosed glass-floored balconies where visitors can look straight down past their toes to the street 412 meters below. Building managers say that the inspiration for the innovation came from the hundreds of forehead prints left on the windows every day by people looking for the sensation of flight. They're also following the lead of several other observation decks around the world, including the Grand Canyon Skywalk, Canada's CN Tower, and Australia's Eureka Tower. If all goes according to plan, "The Ledge" should be completed next month. ]]>