Yes, but other than miners, few people have ever seen the inside of them.

Who Was John R?

You've got Detroit questions, we've got answers. CuriosiD is a podcast from WDET, Detroit's NPR Station. Our reporters answer your questions about the region, like "Who invented the Boston Cooler?" or "Are there really salt mines underneath Detroit?" Something puzzling you about Detroit? Ask about it at http://wdet.org/curious and we might answer your question in a future episode!