The Secret $4BN Tunnel Network Under Chicago

Walk around the streets of Chicago, and you’ll see giant skyscrapers, Wrigley field and lots of deep dish pizza restaurants. But deep beneath all this, the city is hiding something more. 90 meters below your feet, you’ll find a secret underground tunnel network that sprawls 175 kilometers beneath the metropolis and surrounding area that’s part of one of the largest civil engineering projects in the world. Construction has been underway since the 1970s, and in the future it could be a key tool in the fight against climate change. So what is this secret labyrinth concealed below one of America’s largest cities? Why does it exist? And how exactly was it built without anyone noticing? We’re heading underground to find out… read more >