The remains of an ancient Roman city are hidden underneath Bologna's beautiful public library.

The wreckage of a tragic plane crash is on display at this museum devoted to a famous Italian conspiracy.

Potato-peeling mannequins, Inca art, and a dangling tuber mobile help trace the history of fries at this Belgian museum.

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

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.

The patron of this extravagant Art Nouveau confection insisted that nothing less than a boat should project from its facade.

A Belle Epoque bordello turned into a themed love hotel.

Dolls of all shapes and sizes display the eras of femininity in this spooky and beautiful collection.

Inside a former cabaret, seven floors of erotic art.

The approximate spot where the last Grand Master of the Knights Templar was put to death.

In the best of all possible worlds, everyone will get a chance to see this statue in which Voltaire's heart is interred.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

A museum of carnival attractions where you are invited to ride the rides.

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

This massive library holds what was once the largest book collection in the world.

Abandoned railway line circling the city of Paris.

You would never come across this tiny green oasis if you didn't know it existed.

This former Masonic lodge has been transformed into part museum, part bar, all awesome.

A nun spent 16 years painting the stunning Celtic mural that covers the interior of this WWI memorial.

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

An 80-year-old plane tree is devouring an iron bench at Ireland's oldest law school.

The enchanting archway is the only surviving portal into Dublin's lost medieval wall.

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