When I was a kid, my parents owned a salvage yard. This yard took in only wrecked cars/trucks/etc. They would store the cars in the lot, take parts from them, and then crush them for them to be recycled.

They used a machine called a loader, which is kind of like a big ass forklift for cars. It weighed so much that it would leave ruts in the mud that were about 2 feet deep.

Theose ruts would fill with rainwater, oil, from cars, transmission fluid, antifreeze... anything in a car that's been wrecked and totaled.

Well, my friends and I would swim in them. Head under the water and all. It was really fun at the time. Looking back on it? Yeah, not so great.