A kaleidoscopic warehouse-maze of handmade neon signs.

A hands-off space for graffiti artists to hone and display their skills.

This 1920s Dutch barge is now a floating bookstore.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

A student driver's nightmare.

An art world insider finds himself battling for his artistic home.

A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

The celebrated eyesore created by starry-eyed sweethearts.

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

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

This modest marker near Notre Dame identifies the very center of Paris.

Abandoned railway line circling the city of Paris.

An eclectic sculpture park rises atop a giant pile of ashes in Sweden.

This secret facility trained seals for the Swedish navy during the Second World War.

This abandoned urban warfare facility is a dream come true for airsoft and paintball enthusiasts.

These miniature works of art are hiding in plain sight on buildings around the city.

A colossal strolling Pinocchio that was greeted with more outrage than whimsy.

This giant crucifix is like U2's Joshua Tree for Swedish death metal fans.

Sweden's oldest animated sign is still lighting up the skyline today.

Stockholm's tiniest statue is of a small boy looking at the Moon.

Street artists transformed this abandoned industrial neighborhood into one of Europe's largest graffiti exhibitions.

Hundreds of mossy stones engraved with bits of philosophy, literature and random musings.

This homeless brass fox tugs at your heartstrings from the foot of a Stockholm bridge.