A stunning medieval castle owned and restored by the famed actor Jeremy Irons.

After being destroyed by IRA sympathizers, the ruins of this stately Irish manor have sat vacant for decades.

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

An ancient chamber filled with wonderful rock art and a Neolithic carving of a human face.

An Irish church where an 800-year-old mummy is reaching out of his coffin as if to shake hands.

This mysterious hilltop collection of Druid carvings isn't quite what it seems.

The view from this giant Stone Age toad is unexpectedly beautiful.

Although it appears ancient and mysterious, the quirky folly was actually built 200 years ago by an eccentric estate owner.

This knockout museum lies in a sleepy corner of London.

Historic cuisine meets fine dining in a hotel-restaurant overlooking Hyde Park.

Above an abandoned Underground station, this charming bookstore is home to strange antiquities and literary works.

A wildlife paradise, this island is one of the world’s most important habitats for burrow nesting seabirds.

During this yearly Welsh swimming race, competitors tread through the fetid waters of a bog trench.

A renovated henge and stone circle just south of Stanton Harcourt village.

Baked in 1898 and still almost flawless, this floral masterpiece is considered the world's oldest complete wedding cake.

A medieval relic whose great hall once hosted Mayflower pilgrims, one of Henry VIII’s ill-fated wives, and plenty of royal intrigue.

A 19th-century British industrialist built this Louis XIII–inspired chateau for his homesick French wife.

A genuine Little Shop of Horrors.

A traditional American farmhouse plopped in the middle of a Piccadilly courtyard.

This hospital once pioneered the use of electroencephalograms, but fell into maltreatment, abuse, and eventual abandonment.

A hidden tunnel leads to an abandoned slate quarry that's now a secret swimming spot guarded by cliffs.

The decaying ruins of Wales' first asylum for the mentally ill.

Since 1874, this macabre collection has developed into a museum devoted to Scotland Yard's mementos of dastardly deeds.

A memorial commemorating the only Scottish police investigation into an extraterrestrial incident.