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

The remote outlaw hideout of Jesse James, Butch Cassidy, and the Sundance Kid.

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

At high tide this strange footbridge appears to have no purpose whatsoever.

You can walk through the first Boeing Air Force One, which famously carried JFK's casket from Dallas back to D.C.

One of the largest collections of socialist realist art shows the surprising depth of the official art of the Soviet Union.

Dr. Strangelove-esque tours reveal the inside a bunker once reserved for Stalin himself.

This Russian locomotive museum was once devoted just to Lenin's funeral before expanding to encompass Moscow's entire train history.

Rare mummified forest could offers a glimpse into how our environment has been changed by humans.

The closest thing to Mars on Earth.

A Cold War atomic camp buried under the ice is now emerging because of global warming.

This remote research station sits amid the second-largest ice sheet on the planet.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

One of the most horrible legacies of the Cold War is a site where the Soviet Union tested nuclear bombs on civilians.

Conveniently located within binocular range of a nuclear bunker, the "summer camp" area was a painfully obvious spy house.

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

The Cold War-era "underground Pentagon" is a sprawling subterranean hideaway for the Defense Department.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

This controversial Irish show cave is home to a massive formation known as the Great Stalactite.

Certain traditions prevail on the least-visited island of the Aran Islands.

Mortarless walls that stretch for miles are a lovely solution for creating grazing land in the harsh terrain of the Aran Islands.

Bloodstains can still be seen in this medieval church where two medics saved lives on D-Day.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.