The remains of the last Bosnian fortress to fall to the Ottomans are still standing.

This museum preserves the hand-dug tunnel that kept Sarajevo afloat during the Serbian siege.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

Old ships and machinery fill a historic harbor in the city that's home to Europe's largest port.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

Most prolific publishing house in the 1600s open to the public.

From Tintin to the Smurfs, Europe's greatest graphic icons are celebrated in a grand Art Noveau gallery.

A little sculpture with a large wardrobe.

Cozy basement bar sports an inventory of over 2,000 beers.

This modern arts center is built around a gem of late-Baroque architecture.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

This medieval tower is all that remains of the castle where Joan of Arc was held before being burned at the stake.

This bridge was constructed from the rubble of the infamous Bastille.

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.

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

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

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

The celebrated eyesore created by starry-eyed sweethearts.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

Notorious artist squat renovated into legal studios.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The video game-themed street art first popped up in the French city.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.