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

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

Monsters and miniatures are held in equal esteem at this wondrous museum.

This lonely bronze walrus celebrates a character in a Lewis Carroll poem.

A museum and gardens with unusual plants and a history of progressive programming for the blind.

Huge winged monument in the United Kingdom.

The sign at the garden gate reads: “These Plants Can Kill.”

Twice a day this ancient path disappears with the tides, leaving the Holy Island of Lindisfarne out to sea.

This unusual 7th-century Frankish seal offers more questions than answers about its past.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

William Blake claimed to have painted this gothic masterpiece after encountering this nightmarish being in a vision.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

Repository for more than 22 million pickled specimens.

Eighty million natural history specimens call this gargantuan museum home.

The curios of pharmacist and collector Henry Wellcome.

Catacombs turned marketplace.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

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

The cedar tree in Highgate Cemetery earned its title by accident.

A tiny village in Wales claims the name of a noble medieval hound slain for a crime he didn't commit.

The highest peak in Wales is said to be the final resting place of a giant killed by King Arthur.

One of Europe's oldest libraries.

Used as an example in one of the first dictionary entries for "museum" in 1706.