The long underground cave's curiously shaped stalagmites have inspired many legends.

A limestone wonderland of water and subterranean secrets.

This hidden green space is the city's second largest conservatory.

This wildly-tiled artist's palace is a living and growing account of the creator's life, loves, and labors.

Hear the quietest sound from across the dome.

The curios of pharmacist and collector Henry Wellcome.

Catacombs turned marketplace.

A little slice of Japan and its aesthetics in London's Holland Park.

A student driver's nightmare.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

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

Where British troops serving on the remote islands paid tribute to their faraway hometowns.

The sweetest graveyard in the world is filled with headstones for dearly de-pinted ice cream flavors.

The oldest cemetery in New Orleans, resting peacefully for over 200 years now.

A serene but haunting memorial to protective wetland lost, the absence of which directly damaged the Lower 9th Ward following Hurricane Katrina.

A poignant mural honors the heroic teenage non-conformists who took on the Nazis and paid the ultimate price.

The final resting place for a wealthy Roman family, this tomb might be the best preserved of its kind outside Italy.

A church filled with the bones of hundreds of virgins martyrs—or so they say.

This monumental mural crafted nearly 40 years ago is still in perfect condition.

Museum in a swimming pool where the water still flows.

Tables of secondhand books fill the inner courtyard of this 17th-century stock exchange.

Ancient man-made caves underneath small town Belgium.

The birthplace of the titular coat and related products celebrates its claim to fame with a statue of a coat.