In Chicago, size matters. This soaring 110-story skyscraper, designed by Skidmore, Owings & Merrill in 1974, was the world's tallest building until 1996 when the Petronas Towers in Kuala Lumpur, Malaysia, claimed the title. However, the folks at the Sears Tower are quick to point out that Petronas counts its spire as part of the building. If you were to measure the 1,450-foot-high Sears Tower in terms of highest occupied floor, highest roof, or highest antenna, the Sears Tower would win hands down.

Those bragging rights aside, the Skydeck is really something to boast about. Enter on Jackson Boulevard to take the ear-popping ride to the 103rd-floor observatory. Video monitors turn the 70-second elevator ride into a fun-filled, thrilling trip. On a clear day a whopping four states are visible: Illinois, Michigan, Wisconsin, and Indiana. (Check the visibility ratings at the security desk before you decide to ride up and take in the view.) At the top, interactive exhibits tell about Chicago's dreamers, schemers, architects, musicians, and sports stars. Computer kiosks in six languages help international travelers key into Chicago hot spots. Knee-High Chicago, a 4-foot-high exhibit with cutouts of Chicago sports and history at a child's eye-level, will entertain the kids. The Sears Tower also has spruced up the lower level with a food court, new exhibits, and a short movie about the city. Security is very tight, so figure in a little extra time for your visit to the Skydeck. Before you leave, don't miss the spiraling Calder mobile sculpture The Universe in the ground-floor lobby on the Wacker Drive side.