 Chicago has a famous skyline which features many of the tallest buildings in the world as well as the Chicago Landmark Historic Michigan Boulevard District.Chicago's skyline is spaced out throughout the downtown area.The Willis Tower, formerly known as the Sears Tower, the second tallest building in the Western Hemisphere, stands in the western Loop in the heart of the city's financial district, along with other buildings, such as 311 South Wacker Drive and the AT&T Corporate Center.