A Nesting Doll of Churches.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

Two stone columns flank the grand Venice square, but there were supposed to be three.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

Go inside to really appreciate this 500-year-old technological masterpiece.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

The yawning maw of this pagan visage is said to bite off the hands of liars.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

An alchemist's "magic door" stands in the middle of a Roman park.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

The highest peak in the United Kingdom has a history of physics, specters, and a pilgrimage of strange objects.

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

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

The summer tourists on these cliffs are thousands of seabirds.

Eerie ruins of an abandoned medieval fishing village crumble atop an unforgiving stretch of earth.

The heart of a Scottish legend had a centuries-long journey before reaching its final resting place.

A six-ton wedding present for the King of the Scots.

The tomb of one of Scotland's bloody historic villains is a magnet for bumbling desecrators.

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

The final resting place of soldiers' loyal canine companions.

Largest lake in Great Britain measured by surface area.

A pagan tradition of draping trees with rags eerily lives on.

The heads of two giant mythological water horses honor Scotland's horselord past.

Ancient cliffs resembling a kilt on Scotland's second largest island emit an entrancing sound.