This hidden art nouveau gem was designed by an architect in search of a national style.

A museum in the childhood house of a medical pioneer.

A Hungarian pharmacy museum with a box full of mummy powder.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

An antique curios dealer and hybrid taxidermist.

A font of vintage porn on the silver screen.

Walk through spectacular aisles of hanging meat and wagon wheel–sized cheese at the world's largest wholesale food market.

With a history of slaughter, feast, and famine, remnants of the pork industry decorate this area--even its church.

An iconic and eccentric bar for "Manouche" Jazz music keeps expanding its space—and its influence.

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

Indents in the pavement are all that remain from a grisly death machine in Paris.

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

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.

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

Notorious artist squat renovated into legal studios.

The final resting place of many of Germany's most famous communists.

One of downtown Berlin's last reminders of its Communist past.

Named after a militant urban guerilla, this famous former squat is a graffiti-covered stronghold of leftist culture.

From Iggy Pop to David Bowie to Nick Cave, this regal music studio has served some of the all time greats.

A wunderkammer of mysterious objects and stories.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.