The attic of a four-century-old canal house hides a clandestine church.

Amsterdam's Red Light District leaves little to the imagination.

Museum preserving torture methods from the past.

A curious collection dedicated to human and animal anatomy and pathology.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

Gardens representing parts of Asia, Europe, and the Mid East are tucked away among the Soviet-style buildings in East Berlin.

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

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

Floating swimming pool within a moored vessel.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

Super-heavy Nazi architectural experiment.

A tree-like building perches on its trunk in the Steglitz neighborhood of Berlin.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

The fairy tale castle of the "fairy-tale king."

A slice of central Asia in the middle of Berlin.

Got apples?

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

The first green space constructed on an elevated viaduct.

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

Pitié-Salpêtrière was the dumping grounds for women who received the dreaded diagnosis of "hysterical."

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

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

This museum houses an imposing skeleton army comprised of creatures great and small.