There’s a defunct mine underneath Detroit. I’ve read that most of the equipment down there is from the 1940’s. Pristine vehicles that are completely encrusted in salt. They had to be disassembled up top and transported in pieces down an elevator to be reassembled in the mine.
If they ever came into the atmosphere, they would rust almost immediately.
My friend from Michigan said it is a cool place. He been in the salt mine 7nder Detroit.