National Geographic Megastructures

Sears Tower Megastructure Documentary Download
Willis Tower (formerly named, but still commonly referred to as, Sears Tower) is a 108-story, 1451-foot (442 m) skyscraper in Chicago, Illinois. At the time of its completion in 1974, it was the tallest building in the world, surpassing the World Trade Center towers in New York, and it held this rank for nearly 25 years. The Willis Tower is the tallest building in the United States and the fifth-tallest freestanding structure in the world, as well as the fifth tallest building in the world to the roof.

For 20 years, the Sears Tower held the record for the world’s tallest building. Completed in 1974, the 108 stories high building is almost half a kilometer tall. And it still holds the record for having the world’s highest antenna. John Zils, structural engineer and designer of this mega-structure shares some of the secrets about the tower. And get a behind-the-scenes look at some of the various systems and controls that are vital to the building, like security monitoring, the elevators, and the water and power distribution to the various levels, and even the machines that cleans the windows.

Although Sears' naming rights expired in 2003, the building continued to be called Sears Tower for several years. In March 2009 London-based insurance broker Willis Group Holdings, Ltd., agreed to lease a portion of the building and obtained the building's naming rights. On July 16, 2009, the building was officially renamed Willis Tower.

At 1,482.6 feet (451.9 m) tall, including decorative spires, the Petronas Twin Towers in Kuala Lumpur, Malaysia, laid claim to replacing the Sears Tower as the tallest building in the world in 1998. Not everyone agreed, and in the ensuing controversy four different categories of "tallest building" were created. Of these, Petronas was the tallest in one category (height to top of architectural elements, meaning spires but not antennas).

Download Megastructure Sears Tower Documentary

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