Willis Tower, skyscraper in Chicago, located at 233 South Wacker Drive, that was the world’s tallest building until 1996. That year it was surpassed by the Petronas Twin Towers (1,483 feet [452 meters] tall), in Kuala Lumpur, Malaysia. Willis Tower, still called “Sears Tower” by many locals, is the black, bundled-tube skyscraper anchoring the southwest edge of Chicago’s Loop business district. It rises to 110 stories and roughly 1,450 feet to its roof, making it one of the tallest buildings in the Western Hemisphere. The newly redesigned Willis Tower brings a whole new meaning to office space. Come see how Willis redefines the workplace by delivering world-class experiences to the people of Chicago. The Skydeck observation deck at Willis Tower in Chicago, located on the 103rd floor and approximately 412 meters (1351 feet) above the ground, is a transparent glass box that extends outside the building, offering breathtaking city views. The Willis Tower is an International Style skyscraper designed by Skidmore, Owings & Merrill, with Bruce Graham as lead architect, and built between 1970 and 1974, for a reported $175 million dollars, in Chicago, IL. Completed in 1974 by Skidmore, Owings & Merrill (SOM), the Willis Tower, formerly the Sears Tower, is a spectacular achievement in modern engineering and design. The Willis Tower, formerly the Sears Tower, is an interesting amalgamation of architecture and urban progress. It reigned as the tallest building in the world for more than two decades, from 1973 to 1998. The Willis Tower, formerly and still commonly referred to as the Sears Tower, is a 110- story, 1,451-foot (442.3 m) skyscraper in the Loop of Chicago, Illinois, United States. Willis Tower, originally known as the Sears Tower, is a prominent skyscraper located in the heart of Chicago. Standing tall at 1,450 feet, it was once the tallest building in the world and remains one of the most recognizable symbols of Chicago’s skyline. Since its construction in 1973, Willis Tower has been a unique part of the Chicago skyline and was formerly known as the Sears Tower. With a total of 110 floors and an overall height of 527 meters, including its antenna, it was the tallest skyscraper in the world at the time of its completion.