A waterfall 600 ft. inside a mountain, once the bane of gold miners, is now a spectacle of nature.

This vintage train once gave new meaning to “swimming upstream.”

The lowest point in South Dakota and the source of the Minnesota River.

A striking sculpture built to honor the women of the Lakota and Dakota Nations.

A six-ton, 12-foot-tall concrete prairie dog is touted as the largest in the world.

Thanks to a loophole in property ownership, this alleyway has become a cacophonous street gallery.

The ravine where Jesse James supposedly performed an impossible jump to evade capture.

Hidden behind Lincoln's head is a 70-foot-long chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

This replica stave church looks like a piece of Norway was simply plopped down in South Dakota.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

Just a man taking his prehistoric pet for a stroll.

A treehouse assailed by the elements and the government, now gone.

An old soap company building now houses one of Minneapolis’s oldest independent non-profit art galleries.

This 25-foot-tall statue was built as a protest to a property dispute.

Nicknamed the "Grand Canyon of the North," this open-pit mine in Minnesota has a much shorter history.

This tiny Minnesota city tried to secede from the Union as a last-ditch effort to fix its crumbling water system.

Each of these 87 large stones has a unique message. Together, they form part of the Minnesota Military Family Tribute.

Home of St. Urho, the fictional patron saint of Finland.

This Minnesota-shaped forest is actually located in the state it is shaped like.

A piece of solitude and tranquility in the heart of East Saint Paul.

An abandoned fish-shaped drive-in gets a second life as a restaurant.

A giant granite cross remembers missionary Father Frederic Baraga, and his safe passage across an angry Lake Superior.

A nerdcentric group and creators of the Nerd Prom.

The world's largest floating loon bobs in the lake to kick off an annual festival.