A rocky sea serpent hides caves, blowholes, and a spectacular natural bridge.

A subterranean playground in an abandoned slate mine.

Hidden in a grotto 26 feet below Nottingham's oldest hotel, this stylish subterranean drinking den is notoriously hard to find.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

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

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.

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

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

The monster at the center of the Darwin Center Spirit Collection.

One of the world's largest collections of pathological specimens.

Repository for more than 22 million pickled specimens.

A collection dedicated to the treatment of disease, held in London's oldest hospital.

The curios of pharmacist and collector Henry Wellcome.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

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

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

This South London cemetery holds the remains of more than 15,000 people.