An abandoned 1920s school with a mysterious history.

A "Titanic" superfan changed his name to Jack and set up this strange shrine to the blockbuster, complete with Korean food and Tarot readings.

Why a column on the entrance is inscribed with a verse from the Quran is one of Sicily's many mysteries.

A sophisticated astronomical tower built by one of the greatest Persian scholars of the Islamic Golden Age.

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

Notorious artist squat renovated into legal studios.

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

France's most famous cemetery, with some of its most curious tombs.

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

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

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.

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

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.

The lengthy skeleton of one of the tallest Spaniards of all time is on display in Madrid.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

Incredible labyrinth of man made caves.

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

The freeway that never was.