Chicago, the third-largest city in the United States, is home to 1,397 completed high-rises, 56 of which stand taller than 600 feet (183 m). The tallest building in the city is the 110-story Willis Tower (formerly the Sears Tower), which rises 1,451 feet (442 m) in the Chicago Loop and was completed in 1974. Sears Tower was the tallest building in the world upon its completion, and remained the tallest building in the United States until May 10, 2013. The second, third, and fourth-tallest buildings in Chicago are the Trump International Hotel & Tower, St Regis Chicago, and the Aon Center, respectively. Of the ten tallest buildings in the United States, two are located in Chicago. Of the fifteen tallest buildings in the United States, five are in Chicago. Chicago notably has the second tall