Southeast Wisconsin’s Biggest Grid Mystery
We saw Southeast Pennsylvania’s biggest mystery, and now we’re seeing Southeast Wisconsin’s biggest grid mystery. The original poster found this grid in an old school house basement from 1915. It could have been a multitude of things, but it turns out it’s an old heating system.
Those old systems had a wood stove in the basement with wooden vents, to help the heat passively rise. Churches in the area likely had the same structures (via Timmy_The_Tiger_55).