Once the longest bridge in Ireland, this rusting span sits abandoned and overrun by nature.

This ancient Irish religious site is covered in ancient carvings, many of which have barely aged.

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

The ancient tomb acts as a calendar that keeps perfect time.

Just a few miles off the western coast of Ireland lies an isle steeped in Irish literary history.

The personal library of the founder of modern neurology is open to visitors.

Noirish green neon marks the location of one of the oldest private detective agencies in France.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

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

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

Picturesque intersection of witchcraft and ancient Christianity.

This tiny island featuring 9th-century Viking ruins is only accessible at low tide.

Near Birmingham, England three and a half miles of top-secret tunnels housed a World War II “shadow factory” and a Cold War nuclear bunker.

The largest known medieval map of the world.

This crumbling folly looks like an enchanted left over from Middle Earth.

These stark white cliffs were spat up by the sea and are slowly being retaken by it.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

The highest peak in the United Kingdom has a history of physics, specters, and a pilgrimage of strange objects.

The largest stone circle in the world has ended up bringing up more questions than it has answered.

A village on the east coast of England that has almost completely eroded into the North Sea.

This haunting stone chasm is a hotbed of mossy rock and English legend.

One of the oldest and certainly best preserved Cistercian abbeys still in existence.

This tangled English forest looks like something right out of a fairytale.