Sixty years after construction began on one of Chicago's most recognizable landmarks, the towering skyscraper formerly known as the John Hancock Center continues to set new trends along the famous Magnificent Mile. Now officially called 875 North Michigan Avenue, this 100-story architectural marvel remains a defining feature of Chicago's skyline and a symbol of the city's innovation in urban design.

The building's history is filled with fascinating twists that nearly prevented its construction altogether. If the original developers had been able to stick to their initial plans, the iconic skyscraper that Chicago residents know and love today would never have been built. Instead, what emerged was a groundbreaking mixed-use tower that would forever change the landscape of downtown Chicago.

"It has its place solidly in architectural history, the history of this city," said Eleanor Gorski, CEO and president of the Chicago Architecture Center. "It's a recognizable and iconic building, a symbol of Chicago when you think about the skyline." Crain's Chicago Business reporter Danny Ecker echoes this sentiment, noting the building's enduring significance in the city's urban fabric.

For residents like John Harrison, who has called the building home for 18 years, the structure represents much more than just an address. "When you come in and see it, it takes your breath away. It's so majestic in the sky, and it's so unique in the way it looks," said Harrison, a software executive and entrepreneur who also works as an accomplished photographer with work featured in National Geographic. Living in a condo on the 69th floor with west and north views of the city, Harrison has cameras in every room and considers his home "a photographer's dream."

The building's distinctive design features have made it instantly recognizable around the world. Its tapered silhouette – wider at the bottom and narrower at the top – combined with the large exterior X-braces and tall radio and TV antennas, creates a unique architectural profile. Despite its official renaming to 875 North Michigan Avenue, most people still refer to it as the John Hancock Center or simply "Big John." As Harrison notes, "If you say 875, they don't know what that is, but they know the John Hancock building."

The tower's creation was born out of a 1960s urban revitalization effort led by Chicago's first Mayor Daley. "Mayor Daley said we need folks back downtown. We need to show people that Chicago is still a prime city in the Midwest. I need residents down here," Gorski explained. This vision led to the development of one of Chicago's first mixed-use skyscrapers in the Central Business District, combining commercial spaces with residential units in a single towering structure.

Originally, developers from the firm Skidmore, Owings and Merrill planned to build two separate towers on the site located between Chestnut Street and Delaware Place along Michigan Avenue. However, they soon realized there was only enough land for one building, which presented a unique challenge. "How do we get everything in one tower and make most efficient use of the space?" Gorski said. The solution was ingenious: "The lower floors needed to be bigger and accommodate retail and office. The upper floors, where you have views, and light, and air, those needed to be smaller to accommodate residential footprints."

The building's most striking visual elements – the large steel X-braces on the exterior – serve a crucial structural purpose beyond their aesthetic appeal. "When you have cross-bracing, it stops the sway in the wind and takes the place of central columns in a traditional construction," Gorski explained. This innovative engineering approach allowed for more flexible interior spaces while maintaining structural integrity.

Construction faced significant challenges along the way. In 1967, when workers had completed 20 floors, they discovered serious problems in the underground foundation. Construction halted for several months until the issues were resolved, but work eventually resumed. During the construction period, the original owner filed for bankruptcy, and the John Hancock Mutual Life Insurance Company, which had been financing the project, took ownership and eventually moved its offices into the building.

When "Big John" was completed in 1969, it achieved remarkable records. The skyscraper stood as the tallest building in Chicago and the second tallest in the world, surpassed only by the Empire State Building in New York. "It was groundbreaking for the time, and it really set the model for all these other buildings that continue today," Gorski noted, highlighting the building's influence on future architectural developments.

However, change has been inevitable for this architectural icon. In 2018, the John Hancock Company, having already relocated from the building, requested that its name be removed from the skyscraper. Today, the building ranks as the fifth tallest in Chicago and stands as part of the evolving Magnificent Mile district.

The Magnificent Mile itself has undergone significant transformation in recent years. Once the city's premier shopping destination, the area is now dotted with empty storefronts, including some vacant spaces at the base of 875 North Michigan Avenue. "I think, in a lot of ways, the pandemic kind of accelerated what was happening on the Mag Mile, which was retailers were kind of falling victim to the rise of online shopping," Ecker explained. "The vacancy rate was kind of rising, and you add in a lack of foot traffic, add in more instances of crime."

In response to these challenges, the Magnificent Mile is pivoting toward new uses, with 875 North Michigan Avenue leading this transformation. At the top of the building, the famous Signature Room restaurant has closed, but exciting changes are underway. The 360 Chicago observation deck on the 94th floor will be expanded upward to the 96th floor, creating Chicago's first multi-story observation deck. This expansion represents a shift toward what experts call an "experiential environment" – spaces designed to provide unique, memorable experiences for visitors.

"That brings more people into the city, and it also allows folks to use those larger retail spaces that we now see vacated," Gorski said. This approach aligns with broader trends in urban development, where entertainment and experiences are replacing traditional retail as primary draws for foot traffic.

The building continues to house a diverse mix of professional offices, including advertising agencies, law firms, medical practices, and other businesses. The plaza at ground level also hosts artistic events, including the Magnificent Mile Art Festival, further contributing to the area's cultural vibrancy. "They're kind of finding this new path to say this is going to be a different building," Ecker observed.

Despite all the changes over the decades, the building maintains its prestige and appeal. "I think it holds onto that glamour even today. I mean it's a prestigious address, and it's a distinctive place to live," Gorski said. For residents like Harrison, the daily experience of living in such an iconic structure never loses its magic. "Every day, seeing the sunrise and the sunset and that beautiful lake. I love it here," he said.

The building also boasts some impressive statistics and features that add to its legendary status. For those brave enough to tackle the challenge, there are 1,632 steps from the ground floor to the observation deck on the 94th floor – a fact well known to participants in "The Hustle Chicago," formerly called "Hustle Up The Hancock." For those preferring a more comfortable ascent, the building features one of the fastest elevator systems in the world.

As 875 North Michigan Avenue continues to evolve and adapt to changing times, it remains a testament to innovative architecture and urban planning. Sixty years after construction began, this towering achievement continues to define Chicago's skyline while adapting to serve new generations of residents, workers, and visitors. Whether called by its official address or its beloved nickname, "Big John" stands as proof that great architecture can endure and reinvent itself while maintaining its essential character and significance to the city it calls home.