Skydeck Chicago

Once the world’s tallest building, Willis Tower is still way up in the clouds. Though it functions as an office building, the skyscraper’s 103rd-floor Skydeck Chicago draws 1.7 million annual visitors for a trip out onto The Ledge, an enclosed glass balcony extending 4 feet (1.2 meters) out over the city, as well as panoramic views that—on clear days—extend as far as Indiana, Michigan, Iowa, and Wisconsin.