Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.

This extinct volcano rises above Edinburgh and is special for its panoramic views over the city.

The most loyal of little dogs, or a Victorian era publicity stunt?

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

Abandoned railway line circling the city of Paris.

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

With a facade that measures just 107 centimeters, this five-story building is one of the skinniest in Europe.

Vibrant street art created with mixed media.

Of the many chalices in the running for the Holy Grail, this one in Valencia Cathedral sure looks the part.

This house's itty bitty size means no humans allowed.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.

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

This Dutch art piece became a Russian icon.

A line number in Amsterdam that will likely never be used again due to its tragic history.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

Famed for its pie, this eatery has a hidden tunnel that allowed Catholics to secretly walk to church during the Reformation.

The world's largest reflecting pool is just two centimeters deep.

The cutest way to stay safe in traffic.

This home designed for chocolate magnate Antoni Amatller is an exquisite treasure-box of Catalan Modernism.

This Parisian café sticks almost exclusively to an ethos of reuse.

The 28-foot granite map plots the locations of 40 theaters in New York City.

On this romantic tidal island reachable only at low tide the tomb of a famous French writer overlooks the sea.

This small island, a byproduct of 19th-century canal construction, is now home to a charming Japanese garden.