Wacker Drive was conceived of in the 1909 Burnham Plan of Chicago and first opened in 1926. The upper deck was envisioned as a landscaped venue for pleasure driving and local traffic, and a lower section was set aside for through traffic and service vehicles. Many of the adjacent skyscrapers open onto the drive at the basement level to provide easy access to deliveries and garbage trucks.

Local opinion on Lower Wacker is a mixed bag. While a treasured shortcut for some, for the uninitiated the cramped underpass can feel like “making a run on the Death Star exhaust port.” What all can agree on is that the tunnel has a mystic vibe, “a world in itself” wrote the Chicago Tribune in 1962, “a forest of concrete pillars.”

Deeper still beneath Lower Wacker is a little-known third roadway, difficult to find and little visited by law enforcement. Lower Wacker Drive was built in 1975 to provide parking space for garbage trucks and storage for heaps of unneeded trash cans and city property. There’s a strange paradox down here; you’re simultaneously in the heart of downtown and cut off from the metropolis above.

It’s this nearby remoteness that makes Lower Lower Wacker popular among the certain group of drivers who assemble on weekends for high-octane drag races. Residents of nearby apartment buildings can hear the echoing screeches late into the night on Fridays and Saturdays. The Chicago Tribune estimated in 2015 that the racing has been going on “for more than a decade,” but added that nobody can say for certain. The races typically happened on Friday nights, and many participants came from northwest Indiana.

Other than the drag racers, most Chicagoans only visit the lowest Wacker catacomb if their car has been towed to the city’s notoriously difficult to access impound lot, also located on the Lower Lower Drive. Readers might also recognize the area from the extended car chase in Blues Brothers when Jake and Elwood cause a huge pile-up of cars on their way to City Hall.