The city of skyscrapers and classic American food! Chicago is a unique city for sure. It has many nicknames, it seems, and for sure when I was there in April, I could testify that it is the windy city... but there is more!
Book your hotel in advance, especially before any convention! Sounds simple, but hotels there are pricey, similar to Manhattan, and you will want to stay downtown, as it is easier to get around that way. Parking is also at a premium.
O'Hare airport is much further from downtown, so try to fly into Midway if you can.
Best Way To Get Around:
Cab and foot or the L train.