This hidden garden boasts amazing views of Lyon.

Hundreds of hidden passageways weave through the old quarters of Lyon.

An aluminum skeleton brings Chinese mythology to the French shore.

An abandoned swimming pool decays on the outskirts of Berlin.

This little museum is making sure that the art and history of the graffiti sticker is not scraped from history.

This World War II bunker now survives as a documentation of the Nazi regime and war crimes.

A fascinating insight into daily life in the Eastern Bloc.

Art and a pun, all in one.

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

A collection of abandoned typographic signs from Berlin and beyond.

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

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

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

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

An eerie, derelict amusement park in Berlin.

This Parisian gem is one of the most incredible ethnographic museums in the world.

A modern-day Lascaux cave underneath Paris.

This surreal statue brings a famous French novel about a supernatural cad to arresting life.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

A surrealist timepiece by the artist of melting clocks.

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

One of the oldest medical collections in Europe focusing on rare surgical instruments.

Paris' linguistic guide to the international language of, yes, love.