The Old Industrial Park is a location visited in Marceline's past during "The Empress Eyes." It was shown in a flashback and was also a location where Marceline had set up her hobo camp. She explained that she was a vampire hunter during this period and saved a family from an attacking vampire in her song "Memories."
The Old Industrial Park has many abandoned departments such as a pantry, a sewage department, and huge tubes that possibly carried water throughout the facility.
There is also a cylindrical object with a skull and crossbones, possibly hinting at signs of radioactivity, and there are leave-less trees, rocks, and cars scattered everywhere. Marceline's hobo camp is also situated in this park.