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

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

Noirish green neon marks the location of one of the oldest private detective agencies in France.

P-town goes wild for the malassadas at this 87-year-old institution.

This vast collection of smoking pipes from across the world spans centuries.

Cat art as far as the eye can see.

Museum preserving torture methods from the past.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

Tucked in the back of a flower shop, its collection details the fascinating history of the Netherlands's iconic symbol.

This cheese shop also houses a museum devoted to Dutch dairy.

A poignant museum dedicated to the history of the Dutch resistance against Nazi occupation

A floating cat sanctuary on an Amsterdam canal.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

Europe's first floating restaurant is home to a hilarious legend.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

100 massive sculptures in the Hudson River Valley.

The only example of a Paris Métro sign in use at a subway station outside of the French capital. 

This lovely, if imposing, piece of Canadian gothic is possibly the most photographed hotel in the world.

Mysterious 500-year-old tapestries depict a unicorn hunt.

This hidden oasis features a stunning view of the Hudson River and the Palisades from a castle-like museum.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

Visit the monolithic tomb of America's most famous general.

The "Seinfeld" diner.

A curious fountain that has no water and includes Satan, a crab, and 9 giraffes.