This unattributed sculpture in Amsterdam is hiding in plain sight.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

Invisible bridge parts the waters, invoking biblical images and preserving the ominous feel of an ancient moat.

Colorful and chaotic stacked hotel in North Holland.

Inspired by "The Starry Night" this Dutch bike path turns into a glowing work of art each night.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.

Peek through a transparent pyramid and drink in the mountain made of books.

The world's only museum devoted to the wonders of fluorescence.

Despite being considered a thoroughly American sport, basketball's oldest surviving playing field is found in the basement of a Paris YMCA.

Two awe-inspiring globes from the reign of the Sun King hang from the ceiling of France's national library.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

A subterranean shelter remains intact under a busy Paris railway station.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

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

The curious underground history of keeping Paris clean.

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

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

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

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

The very center of Paris is surrounded by a bevy of strange good luck rituals.