The Willis
Tower is a 110 story, 1,450 foot
(442.1 m) skyscraper in Chicago, Illinois. At
completion in 1973, it surpassed the World Trade Center in New
York City to become the tallest building in the world, a title that
it held for nearly 25 years. It was also the tallest building in the Western
Hemisphere for 41 years, until the new One World Trade Center surpassed
it in 2014. While it held the title of Tallest Office Building until 2014, it lost the title of Tallest
Man Made Structure after only 3 years. The CN Tower in Toronto,
which serves as a communications tower, took over the title in 1976.
The
Willis Tower is considered a seminal achievement for
engineer Fazlur Rahman Khan. It is currently the 3rd tallest
building in the United States and the Western hemisphere and
the 23rd tallest in the world. Each year, more than one million
people visit its observation deck, the highest in the United States, making it
one of Chicago's most popular tourist destinations. The structure was renamed
in 2009 by the Willis Group as a term of its lease.
As of April 2018, the building's largest tenant
is United Airlines, which moved its corporate headquarters from 77
West Wacker Drive (then the United Building) in 2012, occupying around 20
floors. Other major tenants include the building's namesake Willis Towers
Watson and law firms Schiff Hardin and Seyfarth Shaw. Morgan
Stanley plans to move to the building in 2019 and become its
fourth largest tenant by 2020.
