A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

Two stunning 17th-century libraries and a cabinet of curiosities.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

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

Medical and zoological curiosities for sale.

A beautiful, dense forest in the shadow of Mount Fuji, with a tragic reputation.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

Try not to get slimed in Tribeca.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

The sign at the garden gate reads: "These Plants Can Kill."

France's most famous cemetery, with some of its most curious tombs.

This faux-seedy Japanese arcade is made up to look like a maze of alleys straight out of a cyberpunk dystopia.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

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

On Japan's Tashirojima Island, cats are king.

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

At the right time of day, sunlight floods through the roof of this cave and illuminates the small pavilion hidden within.

Forever immortalized in concrete, this Simpsons etching was crafted by show creator Matt Groening.

After years of slow decline, a derelict Gothic castle is now being restored to life.

A real-life Professor Snape once taught in this Welsh university building, which students of course nicknamed “Hogwarts.”

A spiral staircase connects the limestone cave with Pembroke Castle, birthplace of King Henry VII.

This neolithic stone grave has been altered and restored so often its now more neo than lithic.