What is the most famous building in Chicago?

The most famous building in Chicago is the Willis Tower (formerly known as the Sears Tower). Standing at 1,450 feet (442 meters), it was the tallest building in the world when it was completed in 1973. The Willis Tower is an iconic feature of the Chicago skyline and is known for its glass Skydeck, located on the 103rd floor, which offers stunning views of the city. The building is a key symbol of Chicago’s architectural and engineering prowess and remains one of the city’s top tourist attractions.