Legend has it fairies gathered at the site of this medieval castle.

This truly palatial work of Communist-era architecture now sits crumbling on a Croatian beach.

Where the lovelorn find a home for their sentimental keepsakes.

A World War II evacuation tunnel turned into a history display of Croatian state and people.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

An abandoned facility that has become a place of ritualistic satanic worship, or so rumor has it.

One of the most important yet well-hidden museums dedicated to the history of medicine.

An abandoned Roman salami factory has found new life as an art space home to 200 squatters.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

The underground sanctuary of a mysterious ancient cult.

No one really knows how these old hobby horses got here, but the herd keeps growing.

This grave in a ghost town cemetery marks the death of a witch on a day that never happened.

This historic cemetery is filled with markers that look more like candy than was likely intended.

Burial ground for revolutionary veterans attracts tall tales, ghost hunters, not enough historians and preservationists.

A painfully obvious spy house sits right across the street from the Russian Embassy.

The last occupied troglodyte dwellings in England weren't abandoned until the 1960s.

Louisa May Alcott based “Little Women” on her experiences growing up in this house with her sisters.

These abandoned grain silos and tunnels are an urban exploration dream.

A tribute to the incredible generosity the Choctaw Nation showed the Irish people during the Great Famine.

Peruse rare tomes like poetry bound in pearls or books with branches and berries growing out of their spines.

One of the foremost Sherlock Holmes collections is hidden away at a Toronto library.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

The walls of this medieval church are covered with perfectly preserved frescos, including a pristine example of the Dance of Death.

The “City of Stairs” sits high in the Andes, above the world’s largest underground copper mine.