Finding Minnesota: The Cave That Pigs Discovered

HARMONY, Minn. (WCCO) – It's been 90 years since three pigs unwittingly discovered one of Minnesota's hidden treasures.

The animals fell through a sinkhole in a pasture in 1924 and their squeals led searchers into a previously unseen series of underground tunnels, now known as Niagara Cave.

For many centuries, water had slowly been chiseling, molding and sculpting through a half mile section of limestone beneath a Fillmore County farm field.

"It's all carved out by the stream," said Mark Bishop, whose family owns the cave. "The water came in from the top, eroding its way downward."

What's left behind is a labyrinth of awe-inspiring tunnels, highlighted by a rare underground waterfall, nearly 60 feet tall.

"That's why they call it Niagara Cave," said Bishop. "It was named after the Niagara Falls in New York."

Bishop was very young when he first visited Niagara Cave as a kid who was into nature.  As a real estate investor in the mid-90s, he learned it was for sale and took another look.

"I went back and told my wife, I said 'I think we're going to buy a cave,'" he said. "I've had three sons working for me, two of them still do."

Ryan and Aaron Bishop, both now in their 20s, grew up to be geology majors, and now they help their parents manage the business.

"This (the cave) is our basement," said Mark Bishop. "This is one of the largest basements in Minnesota, maybe the country."

They now have as many as 30,000 people a year touring their "basement," checking out stalactites, stalagmites and several types of fossils.

"And that's what we're trying to do," Bishop said. "We're trying to encourage people to learn about nature and appreciate nature."

With its continuous water flow, Niagara Cave is still growing, still revealing new features and still inspiring wonder 90 years after those first squealing visitors tumbled in.

In celebration of the anniversary, the family is doing something special on Saturday nights this year.   They turn off all the lights and give people lanterns to carry so they can see how the cave looked to some of the earliest explorers.

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