A submerged archeological park still holds the wonders of a Roman Sodom.

A museum befitting the city responsible for supplying the majority of the world's LSD.

Hidden beneath the streets of London is a secret subway that only carried mail.

Two stunning 17th-century libraries and a cabinet of curiosities.

A New York garbage depot holds a secret collection of weird and wonderful refuse.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

A museum dedicated to the history and exploration of both popular music and science fiction.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

The seamy, underground secrets of Portland's criminal past.

A 16th-century horror show built in a lovely Italian garden.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

A curious collection of locks and keys.

An all-American grocery store in Paris sells U.S. "cuisine" like Pop-Tarts and Heinz ketchup to homesick ex-pats.

An antique curios dealer and hybrid taxidermist.

Inside a former cabaret, seven floors of erotic art.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

This lesser-known Frank Gehry building houses a treasure trove of cinema history.

This Parisian café is dedicated to great tea and the art of knitting.

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

This frog-themed restaurant was frequented by Picasso, Saint-Exupéry, and more.

This recessed garden protects thousands of mountain plants by creating its own microclimates.

The tomb of history's greatest potato promoter is surrounded by tubers.