Ireland's only German military cemetery holds the remains of a spy who was moved there under the cover of darkness.

See some of the world's greatest racing horses at this idyllic thoroughbred breeding facility and garden complex.

The largest portal tomb in Europe has a capstone weighing around 150 tons.

A stunning Victorian abbey and walled garden on a lakefront.

An important pilgrimage site for pagans and early Christians, named for a Celtic goddess-turned-saint.

Local legend says the remains of Father Christmas lie within the medieval grounds.

One of Ireland's most infamous prisons for rebels including men, women and children.

This mysterious abandoned fort looks like something pulled right from Arabian legend.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

Europe's second largest ossuary wasn't discovered until 2001.

Two monstrous faces loom over a village in Czechia.

Countless grotesque faces stare out from this eerie Prague art wall.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

A symbolic graveyard for the villages that perished during the Nazi invasion of Belarus.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

Remnants of successive wars and Muslim colonialism in the 11th century.

A mysterious ancient cemetery with Roman sarcophagi and Lycian inscriptions.

This museum was invented in a novel before being made real by the author.

A Turkish ghost town abandoned in a population exchange with Greece.

This top-secret nuclear bunker hidden in a Bosnian mountain has been converted to a modern art exhibition space.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.