An abandoned network of military bunkers and tunnels open for anyone willing to descend into the darkness.

City Council meetings still happen in this historic building, impeccably preserved on the inside.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

One small town in the Pacific Northwest transformed itself into a Bavarian-themed tourist destination.

Mining caused an asbestos emergency in this small town.

This record-setting hydraulic dam in the Montana badlands was one of FDR's most ambitious public works.

The shortest river in America flows for just 201 feet.

"Polynesia on the Plains."

A smoke stack so large, the Washington Monument could fit inside!

One of the largest collections of wildlife art in the United States, built into the side of a cliff in rural Wyoming.

These giant metal horses graze on a hilltop near the Montana highway.

An entire town preserved as a historic landmark.

Mining town from the late 1890s, once home to Calamity Jane.

For thousands of years, Native American hunters drove buffalo straight off this cliff in Montana's Yellowstone Country.

An apocalyptic seismic event creates a deadly chain reaction that ends with a 6-mile long lake developing within weeks.

A beautiful geyser under environmental threat.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

Native Americans built this circle of stones, which was used to predict astronomical events.

One man's ambition created this psychedelic log home.

Derelict buildings are all that remain of a complex at the site of one of the worst mining disasters in Montana history.