Our Pick
Posted on @rawstates
The Homestake Mine
1876
Lead, South Dakota
Schwerdf · CC BY 4.0 · Wikimedia Commons
The largest and deepest gold mine in North America, worked for 125 years and 8,000 feet down, and the foundation of the Hearst fortune. Physicists later used its depth to shield a neutrino detector, and the shafts now hold an underground laboratory.
That was 1 of the hidden places.
Location: documented spot
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