For nearly 25 years, this black steel giant reigned as the world's tallest building. Today, it remains one of Chicago's most visited landmarks.

Welcome to Willis Tower, the architectural marvel that redefined Chicago's skyline and pushed the boundaries of what seemed possible in skyscraper design. Rising 1,450 feet above the streets of the Loop, this 110-story titan offers more than just breathtaking views.

It represents a turning point in architectural history, where innovative engineering met bold ambition to create a structure that would influence skyscraper construction for decades to come.

From Retail Giant to Architectural Icon

When Sears, Roebuck and Co. began planning a new headquarters in 1969, the retail giant was at its peak with 350,000 employees worldwide. Rather than relocate to the suburbs, the company chose a two-block site on Chicago's western Loop edge.

Construction began in August 1970, and by May 1973, the tower was topped out, claiming the title of world's tallest building. The first Sears employees moved in during September 1973, though not without controversy. Television broadcasters fought the tower's height, fearing signal interference, leading to multiple lawsuits before construction could proceed unimpeded.

The building cost $150 million to complete and held the world's tallest title until 1998.

The Bundled Tube Revolution

What makes Willis Tower truly special isn't just its height but the groundbreaking "bundled tube" design conceived by architect Bruce Graham and structural engineer Fazlur Khan of Skidmore, Owings and Merrill.

The building consists of nine square tubes arranged in a 3x3 grid, with tubes terminating at different heights to create the tower's distinctive stepped silhouette. This was the first building to use this revolutionary design, which proved both structurally efficient and economical.

The exterior showcases 16,000 bronze-tinted windows set in black anodized aluminum, creating the tower's sleek, modern appearance. The innovative structural system has since been used in most supertall buildings worldwide, including Dubai's Burj Khalifa.

The Skydeck Experience

The crown jewel of Willis Tower is the Skydeck observation deck on the 103rd floor, standing 1,353 feet above street level. Since opening in June 1974, it has welcomed over 1.7 million visitors annually, making it one of Chicago's most popular attractions.

In 2009, the Skydeck added "The Ledge," four glass balconies that extend four feet from the building's facade. Standing on these transparent boxes, visitors can look straight down at South Wacker Drive below, an experience that tests even the bravest souls.

On clear days, views extend across Lake Michigan to four states. High-speed elevators whisk visitors to the top in just 60 seconds, where you can feel the building sway in the wind.

Willis Tower Highlights & Tips

• The Ledge Glass Balconies Step onto the glass-floored boxes extending from the 103rd floor for a thrilling view straight down 1,353 feet to the street below. These transparent balconies opened in 2009 and offer an unforgettable photo opportunity.
• Four-State Views On clear days, the Skydeck offers views spanning Illinois, Indiana, Wisconsin, and Michigan. The panoramic perspective showcases Chicago's architectural splendor and extends across Lake Michigan's vast waters.
• The Catalog Shopping Complex The building's base features The Catalog, a modern six-story commercial complex named after the famous Sears catalog. It includes numerous restaurants, shops, and public spaces completed during the 2022 renovation.
• Architectural Innovation Display Learn about Fazlur Khan's revolutionary bundled tube design that changed skyscraper engineering. A sculpture honoring Khan stands in the lobby, celebrating his contributions to modern architecture.
• Best Times to Visit For the clearest views, visit during early morning hours or late afternoon when the light is optimal. Sunset visits offer spectacular photo opportunities as the city lights begin to glow.
• Entry Points The main visitor entrance to the Skydeck is located on Jackson Boulevard on the south side of the building. Tenant entrances are on Wacker Drive and Franklin Street.
• High-Speed Elevators The elevators reach the 103rd floor in about 60 seconds. You'll feel the pressure change as you ascend, so be prepared for the sensation in your ears during the rapid journey upward.
• Photography Tips Bring a camera with good low-light capabilities for evening visits. The bronze-tinted windows may affect color balance, so adjust your settings accordingly for the best shots.

Willis Tower stands as more than just a skyscraper. It represents the moment when Chicago reclaimed its architectural crown and proved that innovation could reach new heights. From Bruce Graham and Fazlur Khan's bundled tube design to the heart-stopping Ledge experience, every aspect tells a story of ambition and engineering brilliance.

Whether you're captivated by architectural history, seeking that perfect skyline photograph, or simply want to stand where the clouds meet the city, Willis Tower offers an experience that connects you to Chicago's bold spirit. Step into the elevator, feel the rush upward, and discover why this 1973 giant continues to inspire wonder in everyone who visits.