Towering over the magnificent city of Chicago, the Willis Tower, often still affectionately referred to by its original name, the Sears Tower, stands as a remarkable testament to engineering prowess and architectural ambition. This colossal skyscraper boasts an impressive 108 stories and reaches a breathtaking height of 1,450 feet (442.1 meters). While standard architectural counts typically recognize 108 floors, the building's owners extend this count, identifying the main roof as the 109th and the mechanical penthouse roof as the 110th, reflecting the sheer scale and complexity of this urban giant.

Upon its completion in 1974, the Willis Tower did more than just add to the Chicago skyline; it dramatically redefined it and, indeed, the global architectural landscape. It magnificently surpassed the iconic World Trade Center towers in New York City to claim the prestigious title of the world's tallest building, a record it proudly maintained for nearly a quarter of a century. Its dominance wasn't limited to global rankings; it also reigned as the tallest building in the Western Hemisphere for an impressive 41 years until the emergence of One World Trade Center in 2013. Furthermore, its highest occupiable floor held a similar distinction until 2022, when it was eventually surpassed by New York's Central Park Tower, marking new milestones in the ongoing quest for vertical ascent.

A Landmark of Engineering Innovation

The vision and structural integrity of the Willis Tower are largely attributed to the genius of engineer Fazlur Rahman Khan of Skidmore, Owings & Merrill (SOM). His groundbreaking work on the tower, particularly the innovative "bundled tube" design, is widely celebrated as a seminal achievement in civil engineering and skyscraper architecture. This revolutionary approach, which essentially bundles nine structural tubes of varying heights together, offered unprecedented efficiency in material use and superior resistance to wind forces, allowing for the construction of incredibly tall, stable, and cost-effective buildings. Khan's design not only made the Willis Tower possible but also profoundly influenced the construction of nearly every supertall building that followed, cementing his legacy as one of the most influential structural engineers of the 20th century. Today, the tower stands as the third-tallest building in both the United States and the entire Western Hemisphere, and it holds the 23rd position among the world's tallest structures, continually inspiring awe and admiration.

An Enduring Tourist Magnet: The Skydeck Experience

Beyond its architectural significance, the Willis Tower is a vibrant hub of activity and a cornerstone of Chicago's tourism industry. Each year, more than one million visitors flock to its renowned Skydeck, located on the 103rd floor. As the highest observation deck in the United States, it offers unparalleled panoramic views that stretch across four states on a clear day, providing an unforgettable perspective of the sprawling urban tapestry below. A highlight of the Skydeck experience is The Ledge, a series of four glass-floored boxes that extend out from the building's facade, allowing visitors to step out into what feels like thin air, 1,353 feet above the streets of Chicago. This thrilling feature has become a must-do for tourists, firmly establishing the Willis Tower as one of the city's most beloved and frequently visited destinations.

Corporate Life Within the Tower

The Willis Tower is not merely a tourist attraction but also a thriving center for commerce, hosting a diverse array of prominent businesses. As of April 2018, its largest tenant is United Airlines, which relocated its corporate headquarters to the tower in 2012 from 77 West Wacker Drive (then known as the United Building). United Airlines occupies a substantial footprint, encompassing approximately 20 floors within the skyscraper. Other significant occupants include the building's current namesake, the global insurance brokerage and consulting firm Willis Towers Watson, which secured the naming rights in 2009. Prestigious law firms such as Schiff Hardin and Seyfarth Shaw also call the tower home, alongside financial giants like Morgan Stanley, which became the building's fourth-largest tenant in 2017. This mix of leading companies underscores the tower's continued relevance as a prime location for businesses seeking a prestigious and strategically located address in the heart of Chicago.

The Enduring Name Debate: Sears Tower vs. Willis Tower

From its groundbreaking construction in the early 1970s until a significant lease agreement in 2009, the edifice was universally known as the Sears Tower. It served as the corporate headquarters for Sears, Roebuck and Company, then the world's largest retailer, from 1974 until 1994, symbolizing the company's vast influence and ambition. However, in 2009, the naming rights were included as part of a lease agreement with the London-based insurance broker Willis Group (now Willis Towers Watson). This change officially rebranded the building as the Willis Tower. Despite this official designation, the building's original name holds a powerful sentimental and cultural resonance, particularly among Chicagoans and those who remember its decades as the Sears Tower. To this day, it is not uncommon for local residents and many long-time visitors to refer to the iconic skyscraper by its venerable old name, a testament to its deep-rooted identity in the city's collective memory.

Frequently Asked Questions About the Willis Tower

When was the Willis Tower built and completed?

The Willis Tower, originally known as the Sears Tower, began construction in August 1970 and was officially completed in May 1973, though it opened for occupancy in 1974.

How tall is the Willis Tower and how many stories does it have?

The Willis Tower stands 1,450 feet (442.1 meters) tall and has 108 stories by standard measurement. The owners, however, count the main roof as the 109th floor and the mechanical penthouse roof as the 110th.

Why was its name changed from Sears Tower to Willis Tower?

The name changed in 2009 as part of a lease agreement when the global insurance brokerage firm Willis Group (now Willis Towers Watson) leased a significant portion of the building and secured the naming rights.

Was the Willis Tower ever the tallest building in the world?

Yes, upon its completion in 1974, it surpassed the World Trade Center to become the tallest building in the world, a title it held for nearly 25 years until 1998.

What is The Ledge on the Skydeck?

The Ledge consists of four glass-floored, glass-walled boxes that extend approximately 4.3 feet (1.3 meters) out from the building's 103rd floor, offering visitors a unique, thrilling, and unobstructed view straight down to the streets 1,353 feet below.

Who was the principal engineer behind the Willis Tower's design?

The principal structural engineer was Fazlur Rahman Khan of Skidmore, Owings & Merrill (SOM), who developed the innovative "bundled tube" design that made the skyscraper's height and stability possible.

Is it true that many locals still call it the Sears Tower?

Yes, despite the official name change in 2009, many long-time Chicago residents and visitors continue to refer to the building by its original name, the Sears Tower, due to its historical significance and cultural impact.