DNAInfo Chicago just put out an extensive interactive map of the full path of the Chicago Pedway - five miles of it. The map shows where the restaurants, shops transit and hotels are along the way, and where to access the underground paths.
"There's a whole world down here that all the people above don't know anything about," said tour guide Margaret Hicks in a 2010 ABC7 interview. "It's really a whole city beneath the city."
It stretches nearly 40 city blocks, centered around the Loop. The Thompson Center is one of the many government buildings connected by the underground walkway system. Head down the escalator, through the food court and you'll spot the official sign.
Part of what makes the system confusing is there isn't always a sign. And there is no "official" map.
"You have to have a really good explorer spirit to you, got to just head down there, give yourself an hour and just be brave," Hicks said.
Every section of the pedway has a unique personality. There was no master plan, which adds to the mystique. But besides getting you from Point A to Point B, you can find quite a bit underground. There's marriage court, Starbucks, Dairy Queen and a super-secret express DMV, and that's just under the Thompson Center. Macy's, the the Daley Center, Millinnium Station, Cultural Center, Aon Center, and the Chase Bank building all include access points, among many others.
You can walk from the Thompson Center, past City Hall, the Daley Center, to the Cook County Administration Building without ever having to step outside. It all began between State and Dearborn. It's the original section of the pedway that started in 1951 between the Red Line and Blue Line, Hicks said.
Today, it's estimated more than 7 million people use it every year.
"It's easy access; it's nice when the weather is bad, don't have to walk outside," said one pedestrian.
The newest section opened in 2009, just steps from the original pedway under Block 37 where you'll find an underground mall with unique shops, like one dedicated to cream puffs.
From Block 37, you can pass under Macy's and head right into another gem of the city, the Cultural Center.
The Pedway system also includes a few satellite sections, like the one near the Art Institutue, that don't connect with the main Loop Pedway.
Other cities with public pedestrian tunnel systems include Montreal - one of the world's biggest - Albany N.Y., Atlanta, Boise, Cleveland, Houston, Dallas, D.C., Oklahoma City, Seattla and Philadelphia. Minneapolis-St. Paul also has networks of skyways that enclose pedestrian traffic above ground, as do Duluth, Rochester and some other Minnesota cities. In many cities, government buildings are the hubs for these tunnel systems.