The building was designed by architect Bruce Graham and structural engineer Fazlur Rahman Khan.
It weighs approximately 222,500 tons.
The antenna height extends the total structural height of the tower to 1,729 feet.
The building was designed to sway up to six inches in high winds to reduce structural stress.
There are over 16,000 windows across the entire building exterior.
Construction took approximately three years to complete, finishing in 1973.
The 103rd-floor Skydeck receives over one million visitors annually.
The glass floor of The Ledge is 1.5 inches thick and capable of holding 10,000 pounds.
The building was originally built as the headquarters for Sears, Roebuck and Company.
Willis Tower, formerly known as the Sears Tower, is a 1,450-foot skyscraper in downtown Chicago that held the title of the world's tallest building for 25 years. The structure features 'The Ledge,' a series of glass-floor observation boxes that extend 4.3 feet out from the 103rd-floor Skydeck. The building utilizes a bundled-tube structural system, consisting of nine interconnected square tubes that provide lateral stability against high-altitude winds. It currently houses over 100 different companies and contains a large retail and dining complex known as Catalog. The building footprint occupies an entire city block in the Loop community area. Its observation deck provides views spanning four states: Illinois, Indiana, Wisconsin, and Michigan. The tower has undergone significant structural renovations in recent years, including the modernization of its lobby and public-facing entertainment levels.
Inside the glass Skydeck Ledge, specifically standing directly over the street view.
Purchase tickets online in advance to bypass the main floor ticketing queue.
Visit on a weekday morning to minimize wait times for the glass-floor Ledge experience.
Download the official interactive app before arriving to learn about landmarks visible from the top.
Avoid visiting during peak weekend hours or major holidays when wait times for elevators and photo opportunities increase significantly.
