Not many Detroit citizens are aware that when they walk of the streets of their humble city, they are walking on top of a 1,500 acres salt mine. The mine stretches from Detroit's metropolitan area, all the way to Melvindale and Allen Park in the South West.
The Detroit Salt and Manufacturing Company shut the mine down in 1983, when the fall of salt prices had caused the company to start losing business. But, the mine was a thriving location in the 1920's all the way up to the 1950's. Allegedly, thousands of citizens would flock to the mines for guided tours, including children on field trips!
The mine, even at it's busiest of times, was according to the worker's clean, and rodent free. One of the reasons the mine was surprisingly rodent free is because rats would have absolutely nothing to eat besides what was left behind by the miners lunch pails. As a result, nothing lived in the mines, nor were there any signs of anything living in past ages.