Okay, so this is the entrance to the mine.

And how many people would we have seen here during World War II?

500 people around the clock.

This would have been humming.

This would have been noisy.

We would smell the fumes from the explosives.

It would be dusty.

This would be not a place we would even be able to stand.

There will be so much activity here.

Back in the 1800s and early 1900s, mining used to be a pretty huge industry in the state

of New Jersey.

In fact, there were almost 700 mines across the state.

Today, all of those mines have closed.

Most have partially or fully collapsed.

But there is one mine here that you can still visit.

I'm Devon DeComo and this is Atlas Obscura, a celebration of the world's strange, incredible

and wondrous places.

Today, we're going to Sterling Hill Mine in Ogdenberg, New Jersey, down into the mine

deep into its history.

And while we're there, we'll also get to see a geological marvel that can't be found

anywhere else in the world.

We'll see you later, after this.

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