The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

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

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Famously misunderstood wonder of the ancient world

Besieged by war, this castle ruin has crumbled into a peaceful picnic spot.

In this cobwebbed old operating theater, you can practically hear the screams of the unanesthetized patients.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

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

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

This Wall Street bar was once a hub of revolutionary activity where Washington famously bid farewell to his troops.

A very classy 1920s-era bar right in Grand Central Station.

The oldest continuously occupied public building in the United States.

This innocuous New Mexico storefront was once the secret jump-off spot for Manhattan Project scientists.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

These picturesque Hawaiian falls are home to a rare species of fish that uses a special sucker to climb up cliffs.

This legendary urban waterfall creates a dazzling display of rainbows.

Hide from the tourist hordes in these relatively unknown, and unguarded lava caves.

This black shoreline is made up of exploded lava particles.

World's largest working waterwheel has been around for over 150 years.