The Willis Tower (originally the Sears Tower), which rises 1,451 feet (442 m) in the Chicago Loop and was completed in 1974, is the city's highest structure. Chicago has the second highest skyline in the United States, after only New York City. The third highest point of elevation in the city is Grant's Tomb, at 954 feet (290 m).
Willis Tower is a landmark skyscraper located on Michigan Avenue in the Chicago Loop community area near Downtown Chicago. It is named after its primary occupant, the Chicago-based insurance company American International Group, or AIG.
The tower is the headquarters of AIG, as well as several other companies that have offices in the building. With 50 floors above ground and a height of 1,451 feet (442 m), it is the tallest building in Illinois and the sixth tallest in the United States. The building was designed by the Chicago architectural firm Graham, Anderson, Probst & White and constructed by the W.R. Grace Company. It is composed of reinforced concrete with stone and glass exterior finishes. The total cost of construction was $140 million ($ today).
American International Group Inc. (AIG), founded in 1945, is a leading international insurance group with operations in more than 80 countries around the world. AIG's three main businesses are Property & Casualty Insurance, Life Insurance, and Retirement Services.
Willis Tower (previously known as the Sears Tower) is a 110-story structure in the center of downtown Chicago. Willis Tower is not simply one of the world's tallest buildings; it is also a gorgeous symbol in Chicago's skyline. The building was designed by the famous Chicago architect Henry I. Miller, who also designed the John Hancock Center. Construction on Willis Tower began in 1968 and it was completed in 1973 at a cost of $40 million ($70 million including fixtures and furniture).
They are not identical structures but rather they are two separate towers that were later connected with a skywalk. The Willis Tower is actually taller than the Sears Tower, which has 108 floors vs 109 for the Willis Tower. The connection between the two towers is called "The Skybridge."
In addition to being a tourist attraction, Willis Tower serves as the headquarters of United Airlines. The top three floors serve as a luxury hotel called "Top of the Willis" while the bottom four do not have any retail space but rather they are used for office space.
Sears Tower is the former name of Willis Tower before it was renamed in 1975 after the Sears, Roebuck & Company store chain that formerly had its headquarters in the building. The two towers are located across from each other on Michigan Avenue near the Chicago River.
Willis Tower is a Chicago, Illinois skyscraper. In August 1970, Sears, Roebuck and Company funded for its construction. The structure was completed in 1973. From 1973 through 1996, it was the highest skyscraper in the world.
Join Britannica's Publishing Partner Program and our professional network to earn worldwide exposure for your work! Willis Tower, previously Sears Tower (1973–2009), is a skyscraper office building situated at 233 South Wacker Drive in Chicago, Illinois, and is one of the world's highest structures. The building is named after its primary tenant, the Chicago-based insurance company J.L. Saunders Company.
Willis Tower was designed by the Chicago architectural firm of Graham, Anderson, Probst & White and built by the Chicago Bridge & Iron Company. It is the third-highest building in the city and has become a symbol of Chicago. The tower's height makes it the tallest building in Illinois and the second-tallest on the Great Lakes shoreline after Toronto's CN Tower (see below). Willis Tower's spire is actually the National Geographic Society's globe headquarters.
It was also the first high-rise to be fully equipped with an elevator control system based on computers. This allowed the management of the building's elevators from any location within the structure. It was also the first building to have an air conditioning system that used freon instead of ammonia. Ammonia systems had been common before this because they were cheaper but they caused health problems for operators working inside the buildings.
The building was opened on August 14, 1973, by Queen Elizabeth II who was in Chicago on her first visit to the United States.