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

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

Architectureal fantasy quarter of Rome.

A church of bones, decorated with 40,000 human skeletons.

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

The shape of this old salt factory complex was inspired by the course of the Sun.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

This neighborhood of futuristic ball houses looks like an alien settlement in a science fiction film.

This stunning 15th-century royal hill fort preserves the age of chivalry in Rajasthan.

This 16th-century monastery has been turned into a surrealist architecture compound.

Home to items never before seen by the public.

This grand gothic brewery has been pumping out suds for over a hundred years.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

The site of the climactic scene from the classic horror film is now a historic landmark.

A mesmerizing reservoir nestled at the heart of a pre-Islamic Yemeni village.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

A man has revenged his true love's betrayal through tears and stone genitalia.

Sweden's "good old days" painstakingly re-created in a model village.

It houses the remains of a 17th-century version of the Titanic.

A hugely vast Irish landscape of barren rock that stretches for miles.

Just a few miles off the western coast of Ireland lies an isle steeped in Irish literary history.

This floating garden in the sky is straight out of a fairy tale, but the real thing is nothing short of magical.

An Iron Age fort on the edge of a seaside cliff offers a glimpse into an ancient, mystical world.

An unusual manor of stunning beauty, born out of a crippling disease.