This irregularly shaped sea fortress has defended not one but three different sovereign states.

This elegant arc of a waterfall marks a religious turning point.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

One-time winter retreats of prolific inventor Thomas Edison and his friend Henry Ford.

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

Paris' linguistic guide to the international language of, yes, love.

The celebrated eyesore created by starry-eyed sweethearts.

Claude Monet was baptized in this lavishly ornate Paris church.

An immersive projection art installation uses sound, scale, and light to take visitors inside classic works of art.

Original cabaret handbills, posters, and feline artwork are a purrfect highlight of the Museum of Montmartre.

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.

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

19th century pendulum and a clock restored by a rogue group of guerilla artists.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Super Robot anime statue guards a forgotten suburban development in Tarragona.

Holy Grotto of Montserrat Monastery holds one of Europe's mysterious black Madonnas.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

In Chicago, a pizza-enthusiast has opened a museum dedicated to the history of pizza.

Once called the "Polish Gold Coast" it is an icon of the neighborhood that bears its same name.

This modest post office sits on the site of H.H. Holmes' famous murder castle.

This historic hotel invented the chocolate brownie.

What's left of the ruins of the 1893 Columbian Exhibition, or World's Fair, also known as the White City.