A mountaintop shrine-temple guarded by a horde of half-demon priests.

This bridge over the River Cuale leads to a neighborhood that was once an escape for Hollywood's elite.

This collection of ancient, mountaintop, underground tombs was once hidden by decades of bloodshed.

Enchanting cave with a river crashing through the roof.

An unusual and beautiful form of mass transit serves the city's steepest neighborhoods.

An explosion of natural color known as "the river that ran away from paradise."

Take a break from all the boring business of death at this funeral home mini-golf course.

What may be America's largest classic video game arcade lurks inconspicuously in a Chicago suburb.

A sprawling museum filled with larger-than-life works of art.

Professional and amateur dioramas, taxidermy, and oddities all located in an attic above a gallery.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

This massive underground salt mine now holds a sci-fi theme park in its depths.

The seamy, underground secrets of Portland's criminal past.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

Haunted Victorian house that inspired a legendary "Ghostbusters" court ruling.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

An ethereal glowing blue ocean cave in Croatia.

When Croatia became independent of Yugoslavia, the splintering governments left behind these concrete tunnels.

Dive for drinks at Croatia's first and only underwater winery.

Longest fortress system anywhere in Europe.

For more than two centuries, the canopy of this venerable tree has been a haven for songbirds and lovers.

One of the world’s longest pedestrian suspension bridges.

A cheese discovery made by shepherds became the pride of a region.

A windswept necropolis carved into the rocks overlooks the "most Portuguese town in Portugal."