Cutting Open a City

One of the things that amazes me about Chicago is all the different levels of the city. There is a whole underground section that you don't normally think of (out off sight, out of mind)... however, the locals utilize the underground areas to avoid traffic (Lower Wacker Drive is a modern architecture marvel in my opinion) and stay out of the elements.

In this particular photo (taken along the Chicago River), it looks as if someone has cut a line through the center of the city and opened it up. You can see 4 different levels.