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

A historic neighborhood church is reborn as a psychedelic arts collective.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

A wondrous old library overlooking the nation's capital.

A cableway for car transport.

After 11 years of reconstruction work, Slovakia's finest hilltop chapel complex is finally reopen to the public.

An unusual cave filled with rare alien-looking aragonite formations.

An extraordinary museum devoted to the pop art legend created by Slovak artists.

Climb around the high waterfalls on series of iron ladders and bridges within the wildest gorge in the Slovak Paradise.

The world's newest astronomical clock is also its most accurate.

A perfectly preserved hill village where the buildings are painted like white lace.

The 700-year-old fortress was the site of Count Orlok's castle in "Nosferatu."

The blood-soaked ruins of the castle where the murderous Blood Countess was walled in alive.

Eighteen mummies have stood guard behind the altar of this tiny church since 1833.

A museum of magic with a Sadist past.

A mechanized clock where a man fights off a dragon, crab, and rooster.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

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

A stunning hermit's shrine on a steep rocky spur in Northern Italy.

The incorrupt tongue of the patron saint of lost things is venerated in this basilica.

This tiny islet has somehow housed an ancient temple, two monasteries, a church, a fortress, and a restaurant.

Skulls and skeletons are omnipresent in this church dedicated to souls trapped in purgatory.

Once known for its horse-powered knife sharpening, this 200-year-old shop offers an array of blades and hard-to-find culinary tools.

The underground sanctuary of a mysterious ancient Roman religious cult contains an exquisite traditional fresco.