Between Neo-Pagans and Neo-Nazis, these strange rock formations have a curious cult following and a very strange history.

A church filled with the bones of hundreds of virgins martyrs—or so they say.

"The most colorful grottoes of the world.

Skeletons dressed in extravagant 18th century royal costumes cavort in the aisles of this German basilica.

A tree-like building perches on its trunk in the Steglitz neighborhood of Berlin.

Where once there was a train station bathroom, there is now this German burger joint.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

The remains of the vast manor that once belonged to Lord Kira, villain in the 47 Ronin story, is now a shrine dedicated to the incident.

Abandoned railway line circling the city of Paris.

Tombstones and enigmatic inscriptions hide within a vault beneath a popular London arts venue.

The London pub overlooks where the Mayflower was moored before setting sail for the New World.

This 1920s Dutch barge is now a floating bookstore.

The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

The 2,000-year-old beam is tucked within the pedestrian entrance to the old London Bridge.

The Great Fire of London and the regulation of one-way streets both started in this alley.

A tangible and sobering reminder of an atrocity that took place during a secret war.

The walls of these four caverns are filled with art that dates back to the earliest human presence in Europe.

Approximately 300 million years ago, a massive coral reef existed in what is now the largest limestone cave in Japan.

Spirits from these lakes are said to produce the local weather and odd phenomena as they bicker between themselves.

The medieval center of the Islamic world was also once the seat of Saladin's sultanate.

The confluence of modernist and traditional architecture in this religious complex reflects the history of both the living and the dead being uprooted, displaced, and rehoused.

This former hotel and casino was part of a paper mill operation that was one of Mexico's largest employers.