Willis Tower

The Willis Tower, formerly known and still often called the Sears Tower, is a 110-story skyscraper in the Loop of Chicago, Illinois, United States. It is 1,451 feet (442.3 m) tall. The building was designed by Bruce Graham and Fazlur Rahman Khan of Skidmore, Owings & Merrill (SOM). It opened in 1973 as the world's tallest building, and it kept that title for almost 25 years.

It is the third-tallest building in the Western Hemisphere and the 26th-tallest in the world. Every year, more than 1.7 million people visit the Skydeck, the highest observation deck in the United States. This makes it one of Chicago's most popular tourist spots. Because it is so tall, it can be seen from far away. It has also appeared in many films and TV shows set in Chicago.

The building sits on a site bounded by Franklin Street, Jackson Boulevard, Wacker Drive, and Adams Street. Graham and Khan designed it as nine square "tubes" grouped in a 3×3 grid, with seven of the tubes stepping back at the upper floors. Its facade is made of anodized aluminum and black glass. The lower part was first used by the retail company Sears, which had its headquarters there until 1994. The upper floors were rented out to other businesses.

The building was called the Sears Tower from when it was built until a 2009 lease included naming rights for the Willis Group. Many local residents still use the old name.

As of April 2019, the largest tenant was United Airlines, which used 850,000 square feet (79,000 m²) of space across 16 floors. Other major tenants included ArentFox Schiff, Seyfarth Shaw, Morgan Stanley, and Willis Towers Watson, the company the building is named after.

History

Sears, Roebuck & Co. had worked from an office complex on Chicago's west side since 1906. By 1966, those offices were too small. Sears decided to bring its many employees together in one building on the western edge of Chicago's Loop. The company bought a site there in 1970. The tower was designed by Skidmore, Owings & Merrill (SOM). Bruce Graham and Fazlur Rahman Khan created its stepped shape. Construction began in August 1970 with the foundation.

Some people worried that the tower would disrupt television signals, and lawsuits were filed. Construction still continued. In November 1972, the Sears Tower became Chicago's tallest building. It was topped out on May 3, 1973, and the first employees moved in that September. Over the following decades, the building changed owners several times and was renovated. In July 2009, it was officially renamed the Willis Tower. This happened after Willis Group Holdings agreed to lease part of the building.

Architecture

The Willis Tower was designed by architect Bruce Graham and structural engineer Fazlur Rahman Khan of Skidmore, Owings and Merrill. It is built from nine square "tubes" arranged in a 3×3 square. Each tube has open floor space with no columns. The tubes set back at different floors. The Sears Tower was the first building to use this design. It was strong, affordable, and taller than the Empire State Building. Many supertall buildings have used this design since, including the Burj Khalifa, which is the tallest building in the world today.

The outside has a facade made of anodized aluminum and black glass. Alcoa made the aluminum sheets. Black bands on the tower help hide its belted trusses. Two TV antennas were added in 1982. The western one was made taller in 2000 to help NBC station WMAQ-TV send a clearer signal. A newer three-level wing has a roof garden. The foundation was built using 201 caissons. Some elevators are double-deck elevators. One freight elevator is reserved for the Chicago Fire Department in emergencies. The lowest floors hold a shopping and dining area called the Catalog. It is named after Sears' mail-order catalogs. The Catalog has a skylight and a coworking space. The Skydeck observation deck on the 103rd floor opened in 1974. It offers views over Lake Michigan, Indiana, Michigan, and Wisconsin. A renovation in 2000 added multimedia exhibits and murals. The design firm also worked on the Top of the World observation deck at the World Trade Center. Glass ledges with laminated glass floors were added in 2009.

Height

When it was finished, the Sears Tower was the tallest building in the world. It was not the tallest structure, though. Toronto's CN Tower was about 350 feet (106.7 m) taller. The Council on Tall Buildings and Urban Habitat (CTBUH) does not count the CN Tower as a building, since it does not have floors from the ground up. The Willis Tower is still the third-tallest building in the Americas and in the Western Hemisphere. Its pinnacle height is 1,729 feet (527.0 m). This makes it the third-tallest freestanding structure in the Americas and the 16th-tallest freestanding structure in the world.

The Petronas Twin Towers in Kuala Lumpur, Malaysia, were called the world's tallest buildings when they were finished in 1998. People in Chicago disagreed. During the debate, four categories of "tallest building" were created. In 2004, Taipei 101 in Taiwan held the record in three of the four categories. In 2007, the Burj Khalifa in Dubai was reported to be taller than the tower in every height category. Later, One World Trade Center in New York City passed the Willis Tower in structural and pinnacle heights. It did not pass it in roof height, observation deck elevation, or highest occupied floor.

Until 2000, the tower did not hold the record for the tallest building by pinnacle height. That record belonged to the John Hancock Center from 1969 to 1978. In June 2000, the tower's western antenna was made taller, to 1,729 feet (527.0 m). This let the Willis Tower just barely take the title.

Climbing

On May 25, 1981, Dan Goodwin climbed the outside of the tower. He wore a homemade Spider-Man suit and used suction cups, camming devices, and sky hooks. He was the first person to climb all the way to the top from the outside, even though the Chicago Fire Department tried several times to stop him. When he reached the top, he was arrested after a climb of about seven hours. He was later charged with trespassing. Goodwin said he made the climb to draw attention to weaknesses in how people are rescued from tall buildings and in firefighting methods. He was later let out of jail after answering many questions from Chicago's District Attorney and Fire Commissioner.

In August 1999, French urban climber Alain Robert climbed the glass and steel outside of the building all the way to the top. He used only his bare hands and bare feet. Near the end of his climb, a thick fog came in, making the last 20 stories slippery.

Since 2009, the tower has hosted SkyRise Chicago, a race to the top of its 103-story staircase. The event raises money for charity. The money goes to the Shirley Ryan AbilityLab.

Naming rights

Sears sold the tower in 1994 and left it by 1995, but it kept the naming rights until 2003. The new owners tried to make renaming deals with CDW Corp in 2005 and the U.S. Olympic Committee in 2008, but those deals did not happen. In 2009, British insurance company Willis Group Holdings rented a large amount of office space on three floors. A Willis spokesman said the naming rights came as part of the negotiations and did not cost Willis anything. The building was renamed the Willis Tower on July 16, 2009. The naming rights were valid for 15 years.

The Chicago Tribune joked that the new name reminded it of the "What you talkin' 'bout, Willis?" catchphrase from the American TV sitcom Diff'rent Strokes. It also said the change was a bad idea in a city that values tradition, where some people still miss the switch from Marshall Field's to Macy's. A CNN article from July 16, 2009, found that some people in the Chicago area were not ready to accept the new name. An October 2010 issue of Chicago magazine refused to use the new name and called the building the "Sears Tower." Time magazine named the change one of the 10 worst corporate name changes. The debate continued into 2013, when Eric Zorn wrote in the Chicago Tribune that the new name had not yet caught on.

Floor plans

Broadcasting

Many radio and TV stations send their signals from the top of the Willis Tower. The lists are ranked by height, from the top down. When stations at the same height share a mast, they use a diplexer to connect to the same antenna. Because the tower is so tall, FM stations (all class B) have very low power.

NOAA Weather Radio station KWO39 sends its signal from the tower on 162.550 MHz. The National Weather Service office in Chicago programs it. The station uses Specific Area Message Encoding (SAME). This can set off an alarm on special weather radios to warn people of a coming danger.

Cultural depictions

The building has appeared in many films and TV shows set in Chicago, such as Ferris Bueller's Day Off, where Ferris and his friends visit the observation deck. Late Night with Conan O'Brien added a character called The Sears Tower Dressed In Sears Clothing when the show visited Chicago in 2006. The building also appears in the History Channel show Life After People. In that show, the tower and other human-made landmarks slowly fall apart without people around, and it collapses about two hundred years after people are gone.

In the 2008 film The Dark Knight, the tower is part of Gotham City. It is shown in many scenes in the 2011 film Transformers: Dark of the Moon. In the 2013 film Man of Steel, the tower is where the offices of the Daily Planet are located.

Position in Chicago's skyline