One of the things Chicago is known for is it’s some what infamous river. The Chicago river (as beautiful as it is today) was once so sludged full of sewage and other waste that rats could run across the build-up on the surface. Humans, on the other hand, had to build bridges to travel to the other side.  Because many large ships used to travel the river regularly, the bridges had to be capable of lifting out of the way for them to pass.

So how do you lift a bridge? Continue reading →