This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

A museum dedicated to the Spanish occult in a town that was terrorized by the Inquisition.

Fascinating town where normal life interfaces with the occult.

Where Agatha Christie mysteriously disappeared in 1926.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

The curios of pharmacist and collector Henry Wellcome.

A musical composition 1000 years in length plays at the Trinity Buoy Wharf in London.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

English antique dealers with a taste for the unusual.

Catacombs turned marketplace.

A clock designed to run with perfect accuracy for 10,000 years.

Charles Babbage's proto-computer, painstakingly brought to life.

A cluttered and astounding collection of antiquities and curiosities.

A mysterious artist-run cabinet of curiosities and library.

This small chapel is built of human bones and decorated with a golden skeleton.

Theme park featuring miniature replicas of European monuments.

The "Little Ones," show Portugal in full miniature splendor.

The world's oldest model village.

New fungal and bacterial species call this deadly lake home.

Started as a kitchen garden, now the second largest botanical garden in the world.

The largest greenhouse in the world is home to over one million types of plants.

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

The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.