The mummified heart of a saint lives on in this church—after a brief hiatus when it was stolen.

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

This singular Irish dolmen is more Frank Lloyd Wright than upright stonehenge.

There might not be much left of these Irish ruins, but their linguistic legacy is still going strong.

An 1814 castle that hosts an exhibit of "explorabilia".

A sacred well steeped in Pagan roots on the West Coast of Ireland.

A cave dug by a man directed by ghosts to find pirate treasure.

The lost American era of gunfighters, bandits, Indians and steam trains is recreated in Sweden.

According to legend, this boat-shaped henge is built over the grave of a mythic king.

A perfectly circular stronghold constructed in the 10th century is now a nucleus of Viking culture housing a museum, village, and reenactment of an epic Viking battle.

This Danish rock field is actually a sprawling ancient cemetery holding the bodies of 700 Vikings.

This Scandinavian island is the site of the first modern observatory.

Opulence and fantasy collide in this royal chair which is supposedly made with unicorn horns.

Submerged busts of communist and socialist figures from the USSR.

Despite centuries of architectural innovation, this French castle is being built like it's the 13th century.

A cave dwelling that was started by the Celts, expanded by monks, and finished by knights.