The longest canal aqueduct in England was built without a plan to get water past the moving boats.

Deep in the countryside lie the remains of one of the grandest Roman dwellings in Britain.

This 11th century tower is said to be the oldest building in Oxford.

Remnants of the Nazis' occupation of Denmark linger along the sand.

This enormous "cloth of the conquest" depicts the Norman invasion of England in mind-blowing detail.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

This medieval tower is all that remains of the castle where Joan of Arc was held before being burned at the stake.

An unusual monument to a 19th-century circus star.

This courtly monument celebrates an influential comedian who turned taking the piss out of the powers-that-be into an art.

The house where the writer spent his formative years.

This lovely, if imposing, piece of Canadian gothic is possibly the most photographed hotel in the world.

This chilly Canadian hotel has a four-month lifespan due to the unusual material it's made of.

Legend says a primate-like cryptid prowls this otherworldy sliver of the Louisiana bayou.

The severed head of a 17th-century Irish martyr lies within an intricate golden shrine.

Ireland's most remarkable collection of these curious cone-shaped houses is worth the buzz.

A standing relief of a Norman knight whose posture marks him as a Crusader.

Certain traditions prevail on the least-visited island of the Aran Islands.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

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

The ruins of an 800-year-old monastery boasts the tallest round tower in Ireland.

A nun spent 16 years painting the stunning Celtic mural that covers the interior of this WWI memorial.

A rocky Irish outcropping with a history of wealth, conflict, and ruin.

An ancient neolithic tomb that only sees the sun twice a year.