Chicago

In one universe, the American city of Chicago existed by 1938.

It included Evergreen Airfield and State Street (where the Benton Cinema was located), and was home to Mr King and his newsstand, where he sold some of the first superhero comics. This included Issue 1 of a Jenny Everywhere comic book comic book.

Just as King was about to sell this comic to a kid, the real Jenny shifted into that universe, and ended up fighting her pursuers in the streets of Chicago, attracting the attention of a police officer, who took up the chase after Jenny for all that she'd incapacitated the original villains. (COMIC: Miss Adventure)

Behind the scenes

By virtue of obviously being a real place, Chicago can be considered a public-domain location in its own right.