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

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

A kaleidoscopic warehouse-maze of handmade neon signs.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

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

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.

"Prepare yourself! You are to become the voice of Interplanetary Parliament."

This peeling mural of Adam and Eve was inspired by the greenhouses at Kew Gardens.

The largest clown school in Britain offering accredited degrees.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

The sculpture of the deceased cockatoo flops atop its personal plinth.

Where condemned pirates met their grisly end at the gallows on the River Thames.

The "lost friend” is the most famous of the six moai statues that were removed from Easter Island.

There's an exclusive Beefeaters pub hidden in the Tower of London.

Three small rooms at the back of the “official” church of London's clowns.

Two plaques commemorate the site of Shakespeare's first theatre.

A network of concealed passageways lies within a busy London Underground station.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

These centuries old gardens have been restored to their 17th century condition.

This ornate English estates "Prodigy House" still bears the cannonball marks of civil war.

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

The chaotic studio of one of the 20th century's most important artists has been preserved down to the dust.

After it was swallowed by a Georgian mansion, this medieval castle remained forgotten for centuries.