With its beautiful rolling hills and bright green grass, it’s no wonder Erin, Tennessee, is sometimes called the state’s own little slice of Ireland. Head downtown, and you’ll discover an awesome piece of the local limestone quarrying history hiding behind a grocery store.

While passing by the local Piggly Wiggly, you may notice something odd: a hole in a huge rock jutting up behind the building. The rock looks out of place, as if it were plunked within a flattened area dominated by business developments.

The rock is actually a large cave, artificially constructed as part of a limestone quarry. You can go inside and view its massive vaulted ceiling. There’s a pool of water within the cavern, which remains a stunning shade of blue on most days. You may spot a paddle boat sitting within its depth, waiting to take to the water despite the cave’s “no trespassing” signs.

The pool of water continues outside the cave, where it bleeds into a large pond. The pond has a couple of ducks you can feed, and you can walk a little path into the trees where you’ll find an area with a smattering of benches.

If you go to the other side of the grocery store, you’ll notice an additional interesting historical feature. There, you’ll see a huge furnace built as part of the old quarry. It has a sign with it explaining the site and its history. There are also two other stacks like this furnace across the street.