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Designed by Skidmore, Owings & Merrill, this multipurpose skyscraper is distinguished by its tapering shape and enormous X braces, which help stabilize its 100 stories. Soon after it went up in 1970, it earned the nickname "Big John." No wonder: it's 1,127 feet tall (1,502 feet counting its antennae). Packed with retail space, parking, offices, a restaurant, and residences, it has been likened to a city within a city. Like the Willis Tower, which was designed by the same architectural team, the John Hancock Center offers views of four states on clear days. To see them, ascend to the 94th-floor observatory—now dubbed 360° Chicago ($19). While there, thrill seekers can pay an additional fee to take advantage of the tower's newest feature, The Tilt ($7), which has eight windows that tilt downward to a 30-degree angle, giving you a unique perspective on the city below. Those with vertigo might prefer a seat in the bar of the 95th-floor Signature Lounge; the tab will be steep, but you don't pay the observatory fee and you'll be steady on your feet.
875 N. Michigan Ave., Chicago, Illinois, 60611, USA