The encased skull that is widely believed to belong to St. John the Baptist.

The world's largest neutrino telescope searches for secrets of the universe at the South Pole.

The hallucinogenic center of the ancient world.

An elaborate shrine dedicated to the four corners of the world unfortunately misses its mark.

An enormous dragon scales the walls of this 17-story temple.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

An optical Illusion once believed to be an electrical phenomenon.

A church that bred legends, and served as an inspiration for the Da Vinci Code.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

Tiny effigies of the victims of Edinburgh's famous Anatomy Murders.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

The most loyal of little dogs, or a Victorian era publicity stunt?

360° views of the city plus five floors of optical illusions and hands-on science.

Protecting the dead from opportunistic body snatchers.

A 18th century graveyard and its astonishing cortege of macabre iconography.

One woman's decades-long obsession with the "La Fée Verte."

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

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

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

A popular shrine where the Blessed Virgin allegedly appeared in 1830, displaying a holy armchair and two incorruptible remains of Lady Saints.

A museum of magic with a Sadist past.

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

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

World-famous, Pink's still manages to keep its prized cult fetish status.