What building is known as the tallest in Chicago?

The Willis Tower, formerly known as the Sears Tower, holds the title of the tallest building in Chicago. Completed in 1973, it reached a height of 1,450 feet (442 meters) including its antenna, making it an iconic symbol of the city's skyline. The building has 110 floors and was the tallest building in the world for nearly 25 years, until it was surpassed by higher structures in the early 2000s.

The design of the Willis Tower, attributed to architect Bruce Graham and structural engineer Fazlur Rahman Khan of Skidmore, Owings & Merrill, is significant not only for its height but also for its innovative use of the bundled tube structure, which allows for both height and stability. The building's observation deck also attracts numerous visitors, offering breathtaking views of Chicago and beyond.

Many other buildings listed have notable heights, but they do not surpass the Willis Tower. The John Hancock Center is a significant architectural design and skyscraper in its own right, but it is shorter than the Willis Tower. Similarly, Tribune Tower and Aon Center, while important landmarks in Chicago's architectural heritage, do not reach the impressive height of the Willis Tower.