Sweden's oldest street has not changed for nearly a millennium.

Veryovkina Cave is more than 1.3 miles deep—the deepest known in the world.

An abandoned village that resides along the mountains of the Aosta Valley.

A rare example of an ancient Japanese hill castle believed to be the fortress of a legendary demon.

This mesmerizing medieval monastery-cave complex sits thousands of feet above ground overlooking a valley.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

This scenic fortress dates back at least 2,400 years to the time of Magna Graecia.

The 3,600-year-old archeological sensation is considered to be the oldest representation of the cosmos.

Legends of treasure and spirits flow from this this fairy tale-like oasis.

Mysterious library of an infamous financier and spiritual seeker.

This natural wonder drops 16 stories straight down through rare flora and streaming waterfalls.

Near this allegedly haunted pub, you can find strong spirits on the rocks.

Get past the gatekeeper's apartment and enter an elaborate hoax of a restaurant with a Masonic feel.

The ruins of this Roman temple dominate the small city in southern Lazio.

One of the most popular megalithic sites in Ireland stands as a humbler version of Stonehenge.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

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

The main gates have been locked since 1745 and will remain so until the Stuart Dynasty returns to the throne.

A fiery crater has been burning in the Karakum Desert since 1971.

A small island abbey is the final resting place of many medieval Scottish monarchs, including the real Macbeth.

It’s said this crypt was the setting for the tragic finale of the Shakespeare play.

Old Danish castle immortalized in Shakespeare's Hamlet.

This ruin in a suburban park may be the place where Shakespeare's "A Midsummer Night's Dream" was first performed.

A decaying garage hidden amid the dense forest is all that remains of a once-prosperous dairy farm.