This imposing castle has stood for nearly a thousand years.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This series of Scottish caves has no clear purpose other than baffling historians.

Spend the night in this formerly abandoned traditional Scottish village.

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

A strange rock with a sinister reputation lurks within the crimson waters of this Scottish glen.

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

These fantastically named natural pools look like something out of a Scottish myth.

This dramatic landscape hidden on the Isle of Skye looks as though you've stepped into the magical realm.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

Iceland's "Smoky Valley" is a beautiful river that is shrouded in a constant cover of steam clouds.

This natural Icelandic fissure allows divers to swim right between two volatile tectonic plates.

This charming woodland trail is peppered with poetry.

These beautiful ruins deep in the Pennsylvania woods are thought to have been a ski lodge or a speakeasy, but no one really knows.

An ancient glacial pothole waterfall in the heart of the Green Mountains.

This New England covered bridge is home to the tale of a jilted lover known to haunt the area.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

These abandoned vessels are destined to be reclaimed by the forest.

Mysterious heaps of stones dot these otherworldly woods.

A black cat protests the City Guild in Riga's Old Town.