The one-time stronghold of the noble Douglas family, now home to ghost sightings and nesting birds.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

A stone copper was sculpted on the wall of the Carlisle Cathedral to honor a local hero.

This temple was constructed entirely by Roman soldiers.

Over a decade ago, painted penguins mysteriously appeared around Berwick-upon-Tweed for no apparent reason.

Twice a day this ancient path disappears with the tides, leaving the Holy Island of Lindisfarne out to sea.

A rocky outcrop where monks hid their most holy relic while escaping Danish invaders.

The medieval-looking hammer beam teak roof may be a Victorian vanity, but it's still absolutely magnificent.

The remains of a Dominican friary, once one of the largest of its kind in the United Kingdom.

This century-old grotesque has a mysterious history and may not actually be a rabbit.

A reconstruction of a classic mansion on the island of Delos was designed for a historian and archaeologist.

This mosque was based on Sub-Saharan Islamic architecture and created for the Senegalese Tirailleurs.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

This mountain trail inspired Nietzsche to complete his magnum opus.

A ruined Maya city that suffered a years-long case of mistaken identity.

One of the world's largest pyramids stands within El Mirador, the "lost city of the Maya."

One of the most breathtaking railways in Europe also takes one of the steepest climbs, from fjord to mountain plateau.

Resting on a hill overlooking the coast, these medieval ruins look completely deserted save for their restored chapel.

This super-sized statue is the only public memorial to the deal that ended America's neutrality during World War II.

The original resting place of Queen Cleopatra and Mark Antony's only daughter.

One of Vietnam's most iconic landmarks was built by Japanese traders and is now in danger of sinking.

This uniquely designed bridge served as the city gate for Comacchio.

A grand entrance to one of the world's smallest Chinatowns.

Many people don't realize there’s a lot going on in—and below—the world’s tallest triumphal arch.