Willis Tower Skydeck

The tallest building in the country, this 1973 landmark put the city in an uproar when insurance broker Willis Group Holdings Ltd acquired the Sears Tower naming rights in 2009. That doesn't change the fact that the building occupies two city blocks and stretches 1,454 feet high. Skydeck views from the 103rd floor allow you to see as far as 50 miles out. While you’re up there, learn about the city’s landmarks from a multilingual computer program and about its history from wall exhibits. If the Skydeck’s newest feature, The Ledge sounds like a horror movie, there’s a reason for that: Crawl into the glass cube structure, and you’re suspended 1,353 feet off the ground.