This narrow canyon has been carved by the river over thousands of years into spectacular and curious forms.

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

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.

A miniature train-ride through Slovenia's largest cave system.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

Amidst the bustling streets of Dublin, there is a hushed garden that is dedicated to "All those who gave their lives in the cause of Irish Freedom."

This is the largest cemetery in Ireland and the first cemetery museum in the world.

The Grand Lodge of Ireland is one of the oldest in the world, full of fantastical, elaborately themed rooms.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

A museum that cashes in on its infamous little people while teaching you a thing or two about the Irish fey.

An Irish church where an 800-year-old mummy is reaching out of his coffin as if to shake hands.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

A museum dedicated to one of Paris’s most famous residents, tucked into a corner of one of the city’s most famous squares.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

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

A mechanized clock where a man fights off a dragon, crab, and rooster.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

A haunting collection of the vanished and disappearing natural world.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.