The manmade caves near the Mississippi River in St. Paul hold a lot of history – and are the home to dozens of ghosts.
We toured the Wabasha Street Caves with tour guide and historian Cynthia Smith, who told us all about the uninvited visitors who hang out in the caves.
Related: Video: A look inside the Palmer House – central Minnesota's haunted hotel
Prominent Twin Cities psychic Echo Bodine told the owners of the caves that there are as many as 25-30 ghosts inside at any given time.
Most of them are nice, but some do like to bug people who visit.
"It's when something happens that can't be explained, that's when we go – oh yeah, it's those uninvited guests again," Smith said.
Hear some of Smith's ghost stories by watching the video above.
History of the caves
Seven manmade caves make up the Wabasha Street Caves. They were mined – using pick axes – in 1849 for the silica, which was used to make glass.
It's among the 80-90 caves in St. Paul that are located near the Mississippi River, but they're the only caves that are privately owned. Most of the others are blocked off to prevent trespassers.
By the late 1800s – after the Wabasha Street Caves were abandoned as mines – they were used as a mushroom farm. Then when Prohibition came along, the owners of the cave opened a speakeasy.
Prohibition came to an end in 1933, so the mushroom farm owners decided to open a legal place to drink, called the Castle Royal.
Smith said it was a classy, expensive space that cost $1 a plate for dinner (that's about $100 today).
And people in St. Paul could afford it. That's because it was full of gangsters who earned their money by stealing it from others.
In 1934, three gangsters were murdered with a Thompson submachine gun while standing near the fireplace in the Castle Royal (you can see the bullet holes in the fireplace). Their bodies are believed to have been buried somewhere in the unfinished caves. (They're not the ones who haunt the caves, though.)
Castle Royal ended up closing in 1940, with the mushroom farm moving out in 1965. During that time, Land O' Lakes also made cheese in the caves.
The caves were abandoned for a few years, but then opened as a disco in the late 1970s. It closed in the 1980s and the caves were abandoned again until the current owners bought it in 1991.
After learning about the caves' history with gangsters – and now the ghosts – the owners got into the event and tour business.
You can visit the Wabasha Street Caves for a historical tour or the lost souls ghost tour (every Sunday in October or the last Sunday of every month).
There are also other events at the caves, including swing night on Thursdays. Find more information on the caves' website here.