This tiny river island switches sovereignty every six months as part of a rare, centuries-old agreement.

This 47-story "M" needed 20 years to be completed

After the famous composer died in Paris, his sister snuck his heart out of the country to honor his wish that it be buried in their native country.

The world’s narrowest house makes for an awkward, four-foot-wide living space.

Naturally formed rock city in Poland.

A mysterious structure left behind on the Polish mountainside, sometimes called "Hitler's Stonehenge".

This mysterious and once-grand memorial still embodies a remarkable architectural vision.

An unusual cave filled with rare alien-looking aragonite formations.

This tower in a small Polish village uses the power of a sacred bell to ward off mischievous weather spirits.

This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.

A historic house devoted to the teachings of a 1700's prophetess and her mysterious box of revelations.

The smallest pub in Britain was once a cabinet of curiosities and it still has the dead cat to prove it.

Thrilling and delicious complement to any dining experience.

Man-made cave with enigmatic carvings, some say made by the Knights Templar themselves.

Vast fan-shaped British cemetery honouring American servicemen lost in World War II.

An extraordinary library and archive dedicated to the history of the Arctic and Antarctic poles.

A complicated contraption for telling time by the moon.

A treasure trove of astronomical, mathematical, and scientific instruments at Cambridge University.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

The sixth of London's "Magnificent Seven" cemeteries, and a source of unlikely inspiration to Beatrix Potter.

An artistic tribute to the famous singer, just around the corner from where he was born.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

The monster at the center of the Darwin Center Spirit Collection.