This 5,000-year-old tomb once had its own hinged door.

A bizarre sculpture garden in the south of France.

A quarry cum sculpture park where the works of art are chiseled into the very walls.

Ancient paintings known as the "Sistine Chapel of Cave Art."

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

Above an abandoned Underground station, this charming bookstore is home to strange antiquities and literary works.

This giant geoglyph of mysterious origins is now the site of neo-pagan rituals.

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

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

Ghosts of France's colonial past.

Former laboratory of radical psychiatrist Wilhelm Reich.

America's most famous piece of self-built architecture.

The largest open-air contemporary art center in Latin America is a unique experience in the Atlantic Forest.

The romantic garden was the epicenter of the Hungarian art scene in the 1880s.

Extraordinary sculpture garden created by an eccentric English poet.

An elaborately decorated house sits on an otherwise quiet street.

These giant volcano sponges in Antarctica are thought to be the world's oldest living animal, at 15,000 years old.

Natural time capsule containing an alien ecosystem.

A tiny, remote island packed with wonders both natural and geeky.

A village of art and exotic creations.

This former limestone quarry is now a subterranean wonderland of grand stonework.

One family's environment-friendly hobbit-house in Wales.

The Stonehenge of Wales is one of the grandest neolithic dolmens still in existence.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.