Hidden beneath the streets of London is a secret subway that only carried mail.

The world's largest collection of witchcraft regalia.

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

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

Where America's first doomsday cult awaited the end of the world.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

This little-known collection holds everything from "Dracula" notes, to the manuscript of "Ulysses," to the forged works of Shakespeare.

The world's third-largest crystal sphere has sat in the Penn Museum since 1927 with the exception of one outlandish theft.

High on a hill overlooking Los Angeles lives a world famous, high power conical Tesla Coil.

An enormous, inside-out glass globe built in 1935.

These fantastically named natural pools look like something out of a Scottish myth.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

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

World's first "penitentiary," meant to be humane, drove men insane.

An exquisite tunnel of cascading flowers.

A psychedelic labyrinth on the San Francisco bay.

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

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

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

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

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.