Willis Tower (formerly Sears Tower), Chicago

Willis Tower is strategically located on Wacker Drive in the heart of the West Loop, Chicago’s premier submarket and home to its largest corporations and commuter rail stations. Completed in early 1973, Willis Tower is an attractive and contemporary 110-story trophy office tower consisting of steel columns and beams in a “mega-module” system. The building contains approximately 3.8 million rentable square feet (“RSF”) including approximately 159,000 RSF of retail space. The Property also features a 160-car executive parking garage accessible from Franklin Street. Other amenities include a world-class broadcast platform, tallest skydeck, full-service conference center, fitness facility, and exceptional technology features.

Completed May 3, 1973, Willis Tower rises to a height to 1,450 feet and is one of the most recognizable landmarks in the Chicago skyline and in the world. The building held the record for the world’s tallest building for 25 years until the Petronas Towers in Kuala Lampur, Malaysia were built in 1998.

In 1982, the antennas added to the building increased its total height to 1,704 feet. In 2000, one of the building’s antennas was extended to 1,729 feet, making it the world’s tallest building to the tip of its antenna. The building held this title until early 2009 when Burj Dubai topped out at over 2,600 feet, making it the tallest man-made structure ever built.

Architects Skidmore, Owings and Merrill (SOM) to produce a structure to be one of the largest office buildings in the world. Their team of architect Bruce Graham and structural engineer Fazlur Khan designed the building as nine square “tubes”, each essentially a separate building, clustered in a 3×3 matrix forming a square base with 225-foot (75 m) sides. All nine tubes would rise up to the 50th floor of the building. At the 50th floor, the northwest and southeast tubes end, and the remaining seven continue up. At the 66th floor, the northeast and the southwest tubes end. At the 90th floor, the north, east, and south tubes end. The remaining west and center tubes continue up to the 108th floor.