With the inaugural Chicago Architecture Biennial set to officially begin this weekend, the city's architectural legacy is poised to take center stage. Visitors and locals will be reminded of Chicago's role in the advancement of modern design, and how the Great Fire of 1871 wiped out thousands of buildings, only to set the stage for redevelopment and a massive comeback. Architects and developers from all over the country came to Chicago to take advantage of the building boom, leading to collaborations that paved the way for the Chicago School of Architecture, as well as innovations that would support some of the world's first high-rise buildings.

Chicago has taken on myriad architectural styles over the last century and a half, and nearly all of them can be seen during a stroll downtown. Curbed contributor Shawn Ursini begins an exploration of the city's historic buildings this week with a walk down Dearborn Street, a main artery in the city's downtown Loop district and a timeline of the built environment. Beginning at Congress Parkway, just north of the historic Printer's Row district, numerous projects and landmarks on this single street highlight the beginnings of the city's skyscraper boom. For any visitors, it's a perfect way to obtain a quick overview of the breadth and depth of the city's architectural treasures. For residents, consider it a chance to rediscover your city (or simply a victory lap).

400-499 Block of South Dearborn (Congress Parkway to Van Buren Street)

BP Gas Station

50 West Congress Parkway

Modern

It may seem counterintuitive to begin a tour of architectural significance at a gas station. But this seemingly out-of-place structure is emblematic of the multifaceted history of Dearborn Street, serving as a reminder of the major mid-century changes to our urban fabric that made cities like Chicago more adaptable to private automobiles.

In the immediate post World War II period, urban renewal led to the construction of interstate highways, many through major urban centers. With the construction of the Congress Expressway, later renamed after President Dwight D. Eisenhower, Congress Street was widened into an arterial road. This extension required the demolition of some of Chicago's oldest skyscrapers along Dearborn, including the 12-story Caxton Building (Holabird & Roche, 1889-1890) and the 13-story Monon Building (John M. Van Osdel, 1890), home office of the Monon Route, a famed railroad running from Chicago to Louisville, Kentucky. Just as car travel would spell doom for passenger trains, the planned route of the Congress Expressway brought about the demise of these early towers.

The east-west parkway was the realization of a key part of Daniel Burnham's famous Plan of Chicago, turning Congress into the city's central axis. In fact, Edward Bennett, who worked on the plan with Burnham, drew out plans for what would eventually become the Congress Expressway, under the auspices of the newly created Chicago Department of Subways and Superhighways. Demolitions began in 1949, and the new expressway to the Western Suburbs was fully completed in 1956.

Manhattan Building

431 South Dearborn Street

Chicago School (William LeBaron Jenney: 1891)

While a number of skyscapers are no longer standing, pedestrians on this stretch of Dearborn can still gaze up at one of the oldest blocks of tall buildings anywhere in the world, many completed during the same period by a small circle of developers. Charles C. Heisen, the developer who commissioned the Monon Building, also built the Manhattan Building in 1889. Measuring 16 stories and 208 feet tall, it was his tallest project to date, and the fifth tallest in Chicago at the time.

Progressive architect and engineer William LeBaron Jenney was commissioned to design the Manhattan. The first to experiment with utilizing an internal metal frame to support a structure's weight, which he used when designing the Home Insurance Building, Jenney was a solid pick to work on such a narrow block. The restricted size of the site led Jenney to add additional structural members to the frame of cast iron columns and wrought iron beams, the first example of wind bracing found in high-rise design. He also used cantilevers in the structure's foundation. The structure was then clad in brick, stone and oriel windows, which became a common feature in Chicago buildings.

In an era before air conditioning, these rounded window bays, which allowed in additional light and improved air circulation, were welcome additions by downtown office workers. The flat Chicago window, a large expanse of glass with a movable sash on either side, was also developing around this time, providing the same environmental benefits.

Plymouth Building

417 South Dearborn Street

Neo-Gothic (Simeon B. Eisendrath:1899 -- Recladding in 1945 by W. Scott Armstrong)

Not quite as tall as its immediate neighbors and less ornamented, the 11-story Plymouth Building clearly illustrates the tripartite facade concept that grew out of Chicago's early high-rise designs. Initially unsure of what the outside of this new generation of tall building were supposed to look like, architects began adopting a design direction which referenced ancient Greece and eventually became a staple of the otherwise modern Chicago School of Architecture aesthetic.

The tripartite concept divides the facade into three distinct parts, like a classical column: a base, a fluted shaft and capital. This stood in stark contrast to the façade of other early tall buildings at the time, especially those in New York, which often repeated the same pattern every three or four stories and then crowned the building with more ornamentation.

The original design of the Plymouth Building included an exterior of ironwork, more reflective of the Chicago School aesthetic. The front façade was re-clad in by W. Scott Armstrong in 1945. Those who want to spy the original design can still check out the original ironwork displayed on the rear façade of the first two buildings.

Old Colony Building

407 South Dearborn Street

Chicago School (Holabird & Roche: 1894)

Constructed by Francis Bartlett, a Boston businessman who named it in homage to his East Coast home, the Old Colony was developed for commercial space. Finishing out the east side of the 400 block of South Dearborn, the early tower boasts rounded window bays, except here the bays were positioned at the ends of the structure, with the north end resembling a pair of turrets. Like the Manhattan Building, the Old Colony's very narrow profile required an innovate solution to brace the structure against the wind. The approach here was slightly different from Jenney's, utilizing a portal arch—a curved piece of steel joining the wrought iron columns to the steel floor girder—for the first time.



The exterior facade has a base of blue stone with brick and terracotta accents cladding the bulk of the structure. Although the building looks tan today, many Chicagoans assumed the building was black, as the exterior quickly fell into disarray after construction, with years of accumulated grime from the industrial city collecting on its exterior.

The building is in the last stages of a full renovation transforming the tower into student apartments, a project that restored the façade to its former glory.

Metropolitan Correctional Center, Chicago

71 West Van Buren Street

Brutalist (Harry Weese & Associates: 1975)

Although technically not on Dearborn Street, the unique edifice of this slice-of-concrete structure is hard to miss. Positioned a half block to the west and set back on a recently rebuilt plaza, the triangular tower has a reinforced concrete facade broken up with thin window slots that seem to reference Medieval siege warfare as opposed to downtown design. The unusual look of the tower is a dead giveaway to its purpose: a high-rise federal jail.

Part of the larger, Ludwig Mies van der Rohe-designed Federal Center complex to the north, the experimental jail was designed with triangular floors that cluster cells around open lounges with a single guard in the center. Harry Weese's firm discovered the layout not only maximized space, but removed blind corners. Cell blocks are located on the building's upper half (inmates stay on floors with smaller, 5-inch wide windows, while administrative staff below work on floors with double-wide openings).

The design was intended to prevent escape, but in December 2012, two inmates successfully repelled 17 floors via tied-together bed sheets. The roof of the tower holds an open-air recreation yard covered in a wire mesh to prevent a more elaborate escape attempt.

State and Van Buren Elevated Station

1 West Van Buren Street

Postmodern (1897, rebuilt 1997)

Chicago's famous elevated train didn't always encircle the city's central business district, nicknamed "The Loop." Initially, a group of private companies ran separate lines that ran through the city, which all came together at separate terminals near downtown. These companies banded together in the 1890's and formed franchises to construct what was called the "Union Loop", a circular line shared by the different elevated lines to facilitate passenger transfers and allow greater access to the business district. The Van Buren leg of the Loop was the last and final piece, with the original State and Van Buren Station opening for service on October 3, 1897.

The new station replaces the original, which was demolished in the '90s. The platforms include metal canopies stretching over the tracks with open steel trusses and skylights running down the peak of the roofline, a visual reference to the train sheds that had been commonplace at intercity passenger rail stations. In 2010, the station was renamed "Harold Washington Library-State/Van Buren" to reflect the adjacent library, named in honor of Chicago's first African-American mayor. To the despair of those hauling piles of books home, a direct connection from the platform the to library that was included in the original plans was never implemented.

300-399 Block of South Dearborn: Van Buren Street to Jackson Boulevard

Fisher Building

343 South Dearborn Street

Chicago School (South Portion DH Burnham: 1896; North Addition Peter J Webber: 1907)

Many of the early, tall structures on South Dearborn Street were occupied by businesses working with paper, usually printing and binding. The offices of the Union Paper and Bag Company, built by Lucius Fisher, was a little different; the company sold the first paper bags, patents for which were issued to Fisher in 1881.

Another 1890's office building with oriel windows, the Fisher was also designed by Daniel Hudson Burnham's firm, and featured far more decorative ornamentation. The facade features bright orange terracotta sheathing, and a playful take on the Fisher name inspired a marine theme for the ornamentation. An equally ornate addition was added a few years later just to the north of the original, standing slightly taller with a flatter façade lacking cantilevering windows.

Village Green, an apartment developer who that specializes in working with older downtown office buildings, converted the Fisher Building into rental housing, preserving many of the interior including the original doors and transoms, which still feature the names of the original tenants.

The Standard Club

320 South Plymouth Court

Neo-Renaissance (Albert Kahn Associates, Inc.: 1926)

The Standard Club, one of a number of private clubs in downtown Chicago, such as the recently refurbished and reopened Chicago Athletic Association, was first established in 1869 and previously occupied spaces on South Michigan Avenue. The growing club eventually moved into its present 13 story-structure on Dearborn Street, which opened its doors to members in 1926. Behind the neo-Renaissance facade lie private dining rooms, a fitness center, and 60 guest rooms for overnight stays.

Monadnock Building

53 West Jackson Boulevard

Chicago School (North Half Burnham & Root: 1889-91; South Half Holabird & Roche: 1893)

This icon on the west side of Dearborn Street here presents the viewer with a single building that espouses two entirely different design directions. Technically, the Monadnock Building is comprised of two separate structures with a clearly visible division, where the ground floor suddenly shrinks in width along the sidewalk.

The Brooks Brothers, another pair of Boston businessmen developing real estate in Chicago, constructed the building and named it in homage to a mountain in New Hampshire. The first portion of the 15-story building was constructed with load-bearing exterior walls and six-foot thick, solid brick sidewalks. These thick walls proved inefficient, eating up valuable square footage, especially on the expensive ground floor, which paid the highest rents per square foot.

It's the conundrum of early skyscrapers in a nutshell. Developers had to build up to make profit on increasingly expensive real estate, but that meant heavier and thicker load-bearing walls, which ate up valuable, rentable space. The metal interior frame used for the second half of the Monadnock, developed two years later, proved to be the ultimate solution.

The second phase of construction utilized a steel frame to take on the weight of the structure. The facade was now a curtain wall, an exterior applied to the structural frame as decoration rather than being used for support. Although the block was developed in two parts, the original construction meant the Monadnock functioned as four separate structures. At one time, there were four entrances and individual building names the other three being the Kearsarge, Katahdin, and Wachusett, all names of other New England mountains.

The Monadnock name now applies to the entire block. You could say the building(s) serve as bookends in architectural history; the north half remains among the tallest load bearing office buildings in the world, while the steel frame of the south half was so structurally efficient, no other high-rise buildings with fully load bearing walls were constructed in Chicago.

After covering some of the historic blocks of Dearborn Street, we'll pick up the tour at Jackson Boulevard and examine midcentury additions to the skyscraper canyon.

— Shawn Ursini

· The Curbed Guide to the Chicago Architecture Biennial [Curbed]

· Installation at Chicago's Garfield Park Illuminates an Architectural Gem [Curbed]

· 18 Hotels to Stay at During the Chicago Architecture Biennial [Curbed]