A chance to sleep among the firs and pines of the Oregon forest.

These enigmatic ruins continue to vex archaeologists.

The largest cave in Northern Europe.

The painter of "The Scream" is laid to rest under a stoic bust of himself in the humble corner of an Oslo cemetery.

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

Artfully arranged bones of 5,800 Austrians.

Handsomely crafted representations of our round planet.

Amidst medieval and baroque buildings, five human-sized gherkins stand tall.

Double spiral staircases are not unheard of, but they are very rare.

A unique opportunity to stay the night in retrofitted sections of sewer pipe.

A strange rock formation with numerous legends trying to explain it.

An intricate and amazing house built by architect Karl Junker.

A sprawling Baroque park with 300-year-old hydro-pneumatic waterworks.

A wunderkammer of mysterious objects and stories.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

The taxidermy remains of the first brown bear to enter Germany in 170 years.

The scars of World War II are preserved on its walls.

A subterranean display of public art and architecture.

The footprint of a frustrated devil in Munich's Cathedral.

Local lore says the devil built this beautiful medieval bridge to help a fleeing bandit.

The home of the morbid art of corpse plastination is open for visitors to view the fascinating, but stomach-churning process.

This artificial cave looks like something out of a fairytale.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

The naval commander’s proudest moment in battle is memorialized in this unique tomb at Arlington Cemetery.