Is it an island or a volcano? That question probably explains why it's uninhabited.

Stalactites and stalagmites in a beautifully lit cave.

An underground city of salt.

One of Canada's oldest museums, the beautiful Redpath has been serving up Natural History and Ethnography since 1882.

A collection of biblical memorabilia.

Museum preserving torture methods from the past.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.

The oldest operating pharmacy in the world features 800-year-old recipes.

The Natural History Museum that time forgot.

The mummified relic of St. Catherine sits forever on a golden throne.

The history and future of cannabis.

Northern Ireland's Brobdingnagian stepping stones.

This museum boasts a bucket of teeth and tells the tale of a 20th-century dental circus.

An eccentric playboy's astounding natural history collection.

His music once banned in Communist Cuba, John Lennon is now immortalized in bronze by Castro, who considers Lennon a "fellow dreamer."

The largest of London's subterranean rivers and once a mad, bad center of London life.

A crucified and bearded female saint.

A 26-foot shark sculpture—a statement about bombs—set off a municipal battle royale.

A treasure trove of pathological, forensic, parasitological, and anatomical specimens.

A 100-year-old chair with joints "cemented by nature."

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

Europe’s oldest natural human mummy.

An enormous, inside-out glass globe built in 1935.