The Michigan Avenue bridge over the Chicago River. Credit: Chicago History Museum

CHICAGO RIVER — Chicago has more drawbridges than any other American city and is second in the world to Amsterdam. On Thursday, the city’s most famous bridge — The DuSable Bridge over the Chicago River on Michigan Avenue — turns 100. 

To commemorate it, Mayor Lori Lightfoot will participate in a live-streamed celebration at 7 p.m. Thursday. She’ll be joined by Department of Transportation Commissioner Gia Biagi, members of the Friends of the Chicago River, Magnificent Mile Association and others. The event will be hosted by McMormick Bridgehouse & Chicago River Museum director Josh Coles.

The bridge at the foot of the Wrigley Building was modeled after spans that cross the Seine River in Paris.

View of street scene on the Michigan Avenue Bridge, spanning the Chicago River, in the Loop community area of Chicago, Illinois, 1927. Credit: Chicago History Museum

Long known as the Michigan Avenue Bridge, in 2010 it was renamed the DuSable Bridge in honor of Jean Baptiste Point du Sable, the city’s first non-Indigenous settler. DuSable lived near the site of the bridge.

Like many bridges in Chicago, it is a grunion bascule bridge that splits into two leaves that are raised on pivots balanced by counterweights sunk below street level.

Bascule bridges do not have a center pier, allowing larger ships to flow through the river, which was crucial at a time when commercial traffic on the river was booming. 

Credit: McCormick Bridgehouse & Chicago River Museum

The balance of the approximately 4,100-ton bridge leaf and 12,000-ton counterweight of the bridge is so precise, it only takes a 108-horsepower motor to open and close each leaf. An engineering wonder even today, the bridge’s massive gears are viewable from inside the Bridgehouse Museum, which is located at the base of the bridge’s southern end.

The most famous bascule bridge in the world is the Tower Bridge in London. The DuSable is probably Chicago’s most important.

It is thought to be the first double-deck, double-leaf bascule bridge ever built, a type known throughout the world as a Chicago style bascule bridge.

First conceived by architect Daniel Burnham in his 1909 Plan for Chicago, the bridge was designed as a gateway between Chicago’s North Side and South Side. Architect Edward Bennett designed the bridge and its four bridgehouses following the Beaux-Arts style and in keeping with Burnham’s concept.

As Lightfoot says in a video promoting Thursday’s event, the bridge “transformed a single, dirt-lane road into the Magnificent Mile at the heart of our downtown and connected the North and South Sides of the city.”

The Michigan Avenue bridge over the Chicago River. Credit: Chicago History Museum

The bridgehouses final ornamental touch was added in 1928, when bas-relief sculptures depicting scenes from Chicago history were installed. Adorning the Bridgehouse Museum is a sculpture titled Defense by Henry Hering, depicting a scene from the 1812 Battle of Fort Dearborn. 

Credit: Flickr/ShyCityNXR

The oldest  bridge in Chicago is the Kinzie Street railroad bridge which dates back to 1908, but has been largely unused since 2000 when then Chicago Sun-Times, the last railroad customer to the east of the bridge, moved its printing plant. 

The DuSable Bridge, by contrast, is used by thousands every day to get from the North Side to the South by car or bus, by downtown workers on foot, and by countless amounts of tourists who stop to take pictures of the skyscrapers that line the river to the west of the bridge and Lake Michigan to the east. 

Credit: Flickr/Rob Pongsajapan