One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

The birthplace of American international flight service has been turned into a celebrity's microbrewery.

This trio of Australian rock spires may have inspired aboriginal legend or just modern tourism.

A Montreal deli that was so beloved that it was allowed to circumvent their laws of language.

The longest and tallest aqueduct in Britain can actually be sailed across.

The smallest post office in the United States is no bigger than a broom closet.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

Apartment complexes built into huge repurposed natural gas tanks.

A stunning cemetery famous for its extraordinarily delicate & lifelike mourning sculptures.

From carts to cars, this leftover Roman bridge in France has managed to survive for centuries.

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

A sprawling nature preserve harbors the world's only living dragons.

Italian cave with exceptional acoustics and an unsavory history.

The world's most active stratovolcano is almost always erupting.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

Every inch of this chapel is covered in craftsmanship from across the world.

"We Seceded Where Others Failed."

A monument celebrating the idea of reaching inaccessible places.

Island ghost town detailing Flagler's folly in building the Overseas Railroad.

The inspiration for the Patagonia Clothing logo, Cerro Fitz Roy turns pink at sunrise.

Oldest building in California still in use.

The final resting place of 121 victims of the RMS Titanic, 42 of which may never be identified.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."