Take the elevator to the 96th floor of the building formerly called the John Hancock Center and order a (pricey) beverage while looking out over the city from some 1000ft up in the sky. It’s especially gape-worthy at night. There's a particularly good southern view from the women's bathroom (sorry, guys).
The place is deservedly popular so be prepared for a crowd. The lounge and restaurant have a separate elevator from the observatory; look for signs that say 'Signature 95th/96th.' Children aren't allowed in the lounge after 7pm.
