By John Dodge
CHICAGO (CBS) — To tell the story of the Chicago River and the city’s bridges, what better place than inside one of the bridges?
Thousands of people pass over the Michigan Avenue bridge each day, and many don’t even realize that are walking right past a museum.
Since 2006, the McCormick Bridgehouse & Chicago River Museum has been basically hiding in plain sight.
Visitors have to look down to see the entrance on the river’s level at the southwest corner of Michigan and Wacker.
The inside of the museum is actually one of the four control towers that guard the iconic bridge.
Visitors enter at the ground level and can climb five floors to the top, offering unique, multi-directional views of Michigan Avenue and the river.
If you stood at the entrance 350 years ago, you would be knee-deep in mud, but even at the beginning, the river was crucial to commerce.
Visitors get a closeup look at the massive gears that raise and lower the double-deck bascule (French for see-saw) trunnion bridge. Amazingly, because the bridge is in just perfect balance, a relatively small motor is needed to lift it.
In the spring and fall, visitors can buy $10 tickets to see the bridge in action when it is raised to allow the tall-masted boats down the river. (Children between 4-12 are $4. Younger ones are free.)
In all, the city maintains 37 moving bridges.
In the early years, city leaders realized they had a couple of major problems.
One was the fact that the grade of the city needed to be raised about 10 feet. If not, there would be no basements or cellars on the South Side.
The river was also filled with raw sewage.
The museum’s displays explain the several steps needed to solve that problem, most notably reversing the flow of the river into Lake Michigan.
Admission is $5 per person, but it is free on Sundays.