This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

The streets of a sleepy Spanish town proudly exhibit some of the world's finest graffiti.

A modern-day Lascaux cave underneath Paris.

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

19th century museum with an eclectic mix of curiosities, from Egyptian artifacts to items on archery history to the skull of the world's oldest horse.

This chain of artificial lakes was an ideal test ground for the aircraft that would carry the "bouncing bombs" used by the WWII "Dambusters" squad.

This beautiful "lagoon" is actually a toxic soup filled with cars, carcasses, and trash. When warnings couldn't stop people from going for a dip, the town dyed it black.

An enigmatic natural rock formation with a manmade passage cut through the center.

Bask in the 19th century grandeur of an eccentric Freemason millionaire's private gardens.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

A perfectly circular lake is formed by the crater of an ancient underwater volcano.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

The medieval castle built as headquarters for the Pope's secretive Knights Templar.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.