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

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

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

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

Take a stroll through the hellish grotesques of Hieronymus Bosch in this elaborate Netherlands church.

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

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

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

A perfectly preserved hill village where the buildings are painted like white lace.

This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.

Poland's oldest salt mine has nearly everything one needs to live underground forever.

An underground city of salt.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

Sculpture designed by Turkish artist and professor Mehmet Ali Uysal.

This giant urban staircase was built to keep the city's brave fighting men from getting waylaid in the red light district.

This ghost town in Belgium will lose its street art when it ceases to exist.

Part modern art project, part traditional chapel, this see-through church is only substantial from the right angle.

Most prolific publishing house in the 1600s open to the public.

Climb inside an iron crystal magnified 165 billion times its normal size.

Each spring, a dreamlike carpet of bluebells overtakes the forest floor.

A magical and peaceful ruined Cistercian abbey in what is now southern Belgium.