Chicago

The Willis Tower (perhaps better known by its former name, the Sears Tower) is the nation's second-tallest building, with sweeping views of Chicago and Lake Michigan from the Skydeck on the 103rd floor.

Brave visitors can check out the Ledge, glass-bottom boxes that offer a hair-raising view 1,353 feet down to the ground below. The city is loaded with cheap eats, and flight and hotel prices tend to track the average temperatures.