Chicago the skyscraper era, which would then be followed by many other cities around the world. Today, Chicago's skyline is among the world's tallest and densest. Some of the United States' tallest towers are located in Chicago; Willis Tower (formerly Sears Tower) is the second tallest building in the Western Hemisphere after One World Trade Center, and Trump International Hotel and Tower is the third tallest in the country. The Loop's historic buildings include the Chicago Board of Trade Building, the Fine Arts Building, 35 East Wacker, and the Chicago Building, 860-880 Lake Shore Drive Apartments by Mies van der Rohe.
The Gogo Building district along the Chicago River. There are two large red brick buildings along the Chicago River just south of where the river splits, formerly known as the Butler Brothers Warehouse buildings. They were both designed for the Butler Brothers Company, a mail order company, similar to Montgomery Ward's and Sears & Roebuck at the time. The northern structure was designed by Daniel Burnham, a famous Chicago architect, with its completion date being 1913, a year after Burnham’s death. This building only stood for 7 years before being completely demolished and rebuilt exactly as it stood before by the Chicago Union