Crain's Chicago has a great article about the opening of the Ledge at the Sears (Willis) Tower Skydeck.
High above Chicagoland on the 103rd floor, this glass cube gives you the opportunity to step out among the clouds. It offers a different perspective on Marina Towers and all the other downtown buildings. Marina City does have a similar perspective with the cantilevered balconies. I have a hard time stepping out to the outermost portion of my balcony...
Check out the video of The Ledge:
http://link.brightcove.com/services/player/bcpid28200935001?bclid=28210826001&bctid=28223913001
