The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

Beneath Denmark's Højbro bridge, a bronze merman and his seven sons forever mourn for the mother and wife who left them for land.

The gilded, masterful astronomical clock will calculate time, dates, and planetary positions for thousands of years to come.

A collection of noses tucked inside an art museum reveals how times have changed.

Microscopic scenes; some call it novelty, some call it art.

A collection of anatomical samples from one of the first anthropologists to suggest that humans reached North America by crossing the Bering Strait.

Ukraine's oldest operating pharmacy now offers guests a fascinating walk through apothecary history.

This tiny museum's sizable collection is jammed into a former underground public toilet.

The pioneer of psychoanalysis spent the final year of his life here, still seeing patients on that famous couch.

An eerie, existential museum dedicated to the author of "The Metamorphosis."

An old asylum graveyard that's been abandoned for half a century attracts those seeking a dark thrill.

The first museum in the world devoted to sexual gadgetry.

A church of bones, decorated with 40,000 human skeletons.

The townhouse where the "Blood Countess" Elizabeth Báthory started her murderous career.

This network of conjoined cellars was riddled with traps and supposedly allowed the townspeople to pretend their homes were deserted.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

The topiary maze at the Habsburg hunting lodge.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

This former insane asylum now holds a pathological anatomy museum.

A steampunk-styled three-floor factory churning out art, activism, and electronic beats.

Dedicated to the history and culture of smoking, this small museum now includes a vape lounge.