5 downtown buildings you should know

Chicago is world-renowned for its architecture, and dozens of iconic buildings in the Loop alone speak to our city’s important role in architectural innovation. Here are five downtown buildings you should know.

By Emily Koval

1. Reliance Building

In the late 1880s, real estate investor and elevator entrepreneur William Hale commissioned Daniel Burnham and John Wellborn Root to design a 14-story building at the corner of Washington and State. In a time when thick coal smoke blanketed the city and skyscrapers were often maligned for casting long shadows on the streets, the architects of the Reliance Building sought to create a building that could be "self-cleaning." The glazed terra cotta cladding provided what was thought to be the perfect solution. It was believed to never need cleaning because its smooth surface would allow any dirt to wash away in the rain. Though that belief ultimately turned out to be unfounded, it inspired the Reliance Building’s most distinct feature, its shining facade of glass and white terra cotta.

2. Monadnock Building

As you pass by the Monadnock Building , you may not be aware that it represents an important, transitional moment in architectural history. Take a closer look though, and it becomes obvious it was built in two phases. The building’s northern half has an unadorned façade, designed by Burnham & Root. Completed in 1891, it features thick, load-bearing walls that were common at the time. The southern half, completed in 1893, is steel frame construction—an emerging technology that Chicago commercial architects had begun using in the mid-1880s. Designers Holabird & Roche adorned the façade with classically inspired ornamentation that accentuated the building’s metal skeleton. Each half, in its own way, demonstrates the transition happening during its time.

3. Aon Center

Distinctively different from its steel-and-glass peers, Aon Center  stands out in Chicago’s skyline. Its history is more colorful than the stark white stone in which it is clad. In the late 1960s, the Standard Oil Company of Indiana decided to build a monumental headquarters in downtown Chicago. The architects used a relatively new structural form for the tower, with elevators and other services bundled together in the core and perimeter columns defining an outer tube. The exterior was beautifully clad in white Carrara marble, the same stone used by famous sculptors for centuries. But the marble could not withstand the Chicago’s extreme temperature swings and cracks began to form. In the early 1990s, the entire building had to be re-faced with durable granite—at tremendous cost.

4. 875 N. Michigan Ave.

If you're looking for a prime example of Chicago's role in innovative skyscraper design, look no further than 875 N. Michigan Ave —formerly known as the John Hancock Center. Skidmore, Owings & Merrill chose a bold form for the building’s design that doesn’t hide how it stands up. The X-bracing on the exterior is more than decoration—it helps the building resist wind loads and reduces the need for internal columns, which opened up the building’s interior and increased available floor space. Engineer Fazlur Khan's "trussed tube system" was an important step in the development of supertall skyscrapers, making it possible to build to unprecedented heights.

5. Vista Tower

Vista Tower is the tallest new development on the Chicago River. At 1,198 feet, it will be Chicago's third tallest building—with the second highest roof in the city—when complete in 2020. It will also be the tallest structure in the world designed by a woman-led firm. Consisting of three vertical columns clad in six varying shades of blue-green glass, Vista joins Jeanne Gang's nearby Aqua Tower in showcasing innovations in natural, organic and geometric forms. It will contain 406 luxury condominiums and a 192-room five-star hotel. Destined to become a new icon on the Chicago skyline, look for the unique "blow-through" floor on the tallest stack, which will lessen wind loads and sway.