The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

A French artist's vague warning hangs over Belleville.

This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

Original cabaret handbills, posters, and feline artwork are a purrfect highlight of the Museum of Montmartre.

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

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.

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

The history of radiation is on safe display at the foot of a radiation science laboratory.

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

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

The oldest stone house in Paris was built by its most famous alchemist.

Notorious artist squat renovated into legal studios.

Tucked in the back of this amazing antique store is an important piece of medical history.

Imagine having a street run right through your home, or better yet, a historic bridge three stories high.

One of Cincinnati's greatest fighters once trained at a now defunct gym in this Over-The-Rhine neighborhood.

Hidden on two floors of downtown building, the library has an incredible deal on rent.

An old Danish political institution where members of government can grab a drink off the record.

Hans Christian Andersen for the postmodern world.

An ultra-modern diversity park in Denmark has turned an entire city block electric pink.

An unusual vending machine designed to support mourners during funeral ceremonies at Zurich's largest cemetery.

Vines grow up the metal bars in this public park created from an old machine factory.

At 929 pounds and 26 feet tall, this stainless steel fork can only be used by the likes of King Kong.

The alpine falls where Sherlock Holmes apparently met his demise can actually be visited.

This is not only one of the oldest collections in Europe, but also possibly the most beautiful.