Willis Tower Skydeck is a real time commitment — fit it in only if it's a priority.
Allow 1–1.5 hours.
The view is the highest in the city and The Ledge — stepping onto a glass floor 1,300 feet up — delivers a real jolt. The catch is the experience around it: long queues, a corralled museum-style approach, and a price that stings if the sky is hazy, so check visibility before you commit.