It was constructed in 1974 with the primary objective of serving as an office. This structure's host city is Chicago, Illinois State University. Willis Tower, designed by Fazlur Rahman Khan, is a significant work. It is named after its principal investor, J.W. "Bill" McDonald.
The original plan called for the tower to be built around a central core, but this portion of the design was changed before construction began. The new design allowed for less expensive materials to be used in its construction.
Willis Tower is currently the second-highest building in the world when measured from base to pinnacle. Only the Petronium Towers in London are higher. The structural system uses large diagonal bracing elements made of tubular steel that are connected by diagonals running vertically throughout the building. The bracing serves to distribute load across a larger area and reduces the need for heavy support columns.
The building is actually three separate towers arranged around a common lobby. The highest of these towers is also the thinnest at 22 stories high. The other two towers are 25 stories each. The total height of the building is 471 feet (143 m). There are only four other buildings in Chicago over 100 feet (30 m) tall: Two 101-story luxury hotels on Lake Michigan, one 110-story office building, and another 112-story hotel.
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 tallest building in the United States, behind One World Trade Center and The Trump Building. When it was completed in 1973, it was the second tallest building in the world behind La Défense in Paris, France. The building has been called "the last great commission of Chicago architecture" and "one of the most innovative buildings of its time."
Willis Tower has 24 floors below ground and 102 stories above it. Its height makes it the tallest building in both Chicago and Illinois, as well as the seventh-tallest in the United States. The building's size also makes it the largest interior space holder in Chicago when measured by floor area. At the time of its construction, it was the most expensive single structure ever erected in the city.
The building was originally planned by Johnson & Johnson CEO William C. Gieseke with his friend and colleague Daniel H.
An American Icon with a Long and Prominent History Willis Tower is located in downtown Chicago and represents the future of work and recreation. The 110-story building is one of the world's tallest structures and the second-tallest structure in North America, making it difficult to overlook when admiring the city's skyline.
The Willis Tower is home to several companies and organizations including: AT&T, Ernst & Young, H&R Block, IBM, Marsh & McLennan, Navteq, Northwestern University, Roche Diagnostics, SAP, and Sprint. It also hosts many events including the annual Thanksgiving Day Parade and the Lollapalooza music festival.
Willis Tower gets its name after William Wrigley, Jr., who donated $10 million for its construction. The building was designed by Helmut Jahn and opened for business in 1990. It is currently owned and managed by a non-profit organization called CIM Investments Inc. (Chicago Investment Management).
In addition to being used for offices, the Willis Tower provides space for shops, restaurants, a hotel, a museum, a observatory, and even a sculpture garden. Visitors can access the tower's observation deck on each floor or take the glass elevators for a vertical journey up into the heart of the building.
Willis Tower has been listed as a National Historic Landmark and is considered to be one of the most influential buildings in the United States.
Willis Tower (previously known as the Sears Tower) is a 110-story structure in the center of downtown Chicago. It is the second-highest building in the city and the third-largest concrete structure in the world. The tower was named after its primary occupant, insurance company American International Group (AIG).
It was designed by the Chicago architectural firm of Graham, Anderson, Probst & White and constructed by the Chicago Bridge & Iron Company. The foundation consists of 20,000 tons of structural steel attached to the bottom of Lake Michigan, which serves as an efficient wave barrier. The tower's height makes it the highest point in Illinois, except for Alta Peak in East Boulder County near Fort Collins, Colorado.
When it was completed in 1973, the Willis Tower was the tallest building in the Western Hemisphere. It has since been surpassed by two other buildings in New York City: One World Trade Center and 72nd Street Station. The Willis Tower remains the fourth-tallest building in America and the seventh-tallest in the world.
In 2009, AIG announced that it would move its headquarters from New York to Chicago's new Donald Trump Tower.
The Willis Tower 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 renowned architect Helmut Jahn and built from 1989 to 2014.
Willis Tower is so named after its original owner, John W. Willis. The tower has been listed on the National Register of Historic Places since 2004.
It is currently owned by a partnership including affiliates of Apollo Global Management LLC and GSO Capital Partners. The building is managed by CBRE Group Inc. The top three floors are restricted access and offer views of Chicago. There are public viewing rooms on each floor of the building.
Willis Tower was the world's tallest building for nearly 10 years starting in 1990. It was surpassed by the Burj Khalifa in Dubai in 2008 but regained the title back in 2013 when it was completed.
In September 2016, a joint venture between Chicago real estate investment firms SL Green and Rockwood Center purchased the building for $150 million. The new owners plan to renovate and rebrand the tower as a mixed use development called "Tribune Park".
The Sears Tower first welcomed tenants in 1973, however construction was not finished until 1974. It is composed of two equal parts: an upper section with 72 floors and a lower section with 52 floors.
The tower was named after its original tenant, Sears Roebuck & Company. When Sears moved out in 1990, they were replaced by another retailer who also filed for bankruptcy protection in the same year: Neiman Marcus. The store closed in 2009 when its lease expired. Since then, the building has been known as the Willis Tower.
Construction on the Sears Tower began in 1969 and it was completed four years later at a cost of $150 million. At the time it was built, it was the tallest free-standing structure in the world. It remained that way for over 10 years until the Petronia Towers were completed in San Francisco and Toronto respectively. The Willis Tower still holds the record for the tallest building within city limits (though not overall).
After 40 years under Sears' name, in 2013 they announced that they would be changing the name to Residences at the Park. The new name is being used for marketing purposes only and the company remains Sears Holdings Corporation.