One Tank Trip: Cave of the Mounds

September 1, 2011

It's a national, natural landmark, and it's all underground. Welcome to Cave of the Mounds.

Within the wide open prairie of southwestern Wisconsin lies a hidden jewel that began forming 2 million years ago 30 feet underground. Cave of the Mounds was discovered by accident in 1939 during a routine quarry blast on Brigham Farm.

"They set their charge, drilled their holes, put in the dynamite and exploded the charge and were just astonished when the dust settled to see a big gaping hole where they were expecting a pile of rubble," said Joe Klimzcak, general manager, Cave of the Mounds.

What they discovered instead was a huge limestone cavern filled with dramatic crystal formations. As word of the discovery spread, curiosity seekers from miles around came to see the geological wonder. A year later, lights and walkways were installed, and Cave of the Mounds was opened to visitors.

It takes about an hour to go through the entire cave, and one other thing: Don't forget your jacket because it's 50 degrees in there year round.

As you venture through the winding passageways, you'll see amazing stalactites piercing from the cave's ceiling, along with the oddly shaped, but no less fascinating stalagmites pushing up from the ground.

"These dripstone stalactites and stalagmites form when little bits of limestone are dissolved by rainwater that percolates through the ground and comes into the cave," said Klimzcak.

The formations grow at a painstakingly slow rate -- 100 years per cubic inch. And they all have a story to tell. The stalactites along the crack in the ceiling show where the cave formed. The ribbon stalactites are known as "cave bacon." And there are millions of fossils. One cephalopod, or giant squid fossil, dates back 400 million years.

The rules in the cave are "no touching" because the oils in our hands will prevent the formations from continuing to grow.

Around every turn holds a new discovery. Calcite on standing pools of water forms cave lily pads! The painted waterfall gets its deep orange, red and blue hues from bits of iron, manganese and other trace minerals mixed in. Once you've completed your tour of the cave, there's plenty to do above ground. There are trails through the prairie and a geological time line, complete with dinosaur footprints for kids to follow. You can look for treasures in the old-fashioned gemstone mine, or you can find a secret treasure hidden inside a geode.

Just a few miles down the road is Mt. Horeb, known as the troll capital of the world. Seventeen life-sized trolls line Main Street, otherwise known as The Trollway.

Mt. Horeb's business district used to be the main highway between Madison and Dubuque, Iowa. When the state built a bypass around the village in the 1980s, some savvy business owners drew upon the Norwegian heritage of the area and created The Trollway to draw visitors through the town instead of around it.

And just outside of Mt. Horeb is the outdoor museum known as Little Norway. About a dozen quaint log buildings, which were once a pioneer homestead, are now open to the public. The main building has a Chicago connection. "The building we have here is the Norway Building from the 1893 Chicago World's Fair. It was build for the World's Fair," said Gretta Krantz, tour guide, Little Norway.

The Scandinavian heritage is abundant in this region of Wisconsin. Mt. Horeb is celebrating its 150th anniversary this year with several weekend festivals. Cave of the Mounds is open for tours year round, and that 50-degree temperature feels pretty good in the middle of winter.

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