The John Hancock Center Tower is maybe not Chicago's most beautiful building but is one of the most recognizable. After the Sears Tower, and the Aeon Building, the Hancock is the third tallest building in Chicago and in the US. While the Sears Tower is a place of business, the Hancock is a place to do business to but also to live. Yes, that 100 floors and 1,127 feet tall building has year-round resident. And I understand the prized apartment are the one where the windows are crossed by those X beams so characteristic of this building. It has everything you need too (Post office, dry-cleaning, newstand... even a grocery store! The ground floor has restaurants and business.
But people come here for the view, the best view in town. You have the choice, you can either pay the admission price for the observation deck (open from 9 am to 11 pm): Adults pay $9.50, Seniors (62+); $7.50 and children under 12-years-old; $6.00. The alternative is enjoying a drink or a meal at the Signature room on the 95th and 96th floor and 96th-floor (restaurant on the lower floor and lounge on the upper floor). It's not cheap (more than 6 bucks for a beer) but you can have a drink with a view! On the other side, if you really want a 360 degrees view, then the observation deck will be your pick. You may also notice that the building is... yes... swaying. Especially if the wind is strong. Don't worry though, the worse thing you can get is maybe a little motion sickness.
I recommend going at sunset when the sun disappears and the Chicago lights are coming on, it's really, really a sight to see!