America's Tallest Building (3) tv-pg Play video Select your TV provider to log in to have full access to videos Select your TV provider See all providers Don't see your TV provider? Learn more You can access this video on the free HISTORY® apps. *You must verify your TV provider towatch this video on the App Your Parental Control settings do not allow you to view this content. America's Tallest Building (3 min) tv-pg Chicago's Willis Tower, formerly named the Sears Tower, was the tallest building in North America. What does it take to maintain and operate this massive skyscraper?