These mouldering mansion ruins remember a time when the Catskills were nothing but luxury.

The walls of this medieval church are covered with perfectly preserved frescos, including a pristine example of the Dance of Death.

A miniature train-ride through Slovenia's largest cave system.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

This one-time health resort was used by aristocrats around the world.

This massive subterranean fissure is known as the "underground Grand Canyon."

The ruins of a 13th-century monastery that long served as a place of refuge from wars and raids.

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

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

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

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

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

Religious perseverance and cultural coexistence manifest in an architectural gem that multiple wars couldn't topple.

Despite being pillaged and destroyed a number over times down the centuries, this historic church still sort of stands.

A Serbian church lit by chandeliers made of weapons.

A sinuous path among steep cliffs creates a stunning sight in southwestern Serbia.

Structure built from the skulls of vanquished foes.

This 14th century castle withstood years of battle but is now sliding off the hills into the Danube.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

A medieval church built up to defend its village.

Known as the Hintz House, this medieval pharmacy has been an apothecary's haven for nearly 450 years.

A stunning 18th century pharmacy and medieval chemist's collection.

Romania's "Red Ravine" is a little-known natural wonder that bears a resemblance to the Grand Canyon.

The Natural History Museum that time forgot.