The world's second-largest sundial, made entirely out of stone.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

A set of ancient drawings in the desert of Peru that are so massive, many of them can only be fully seen from the sky.

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

A museum of alchemy and a basement laboratory all housed in an ancient building in a Gothic tower.

Macabre astrological automaton clock dating to the late 1400s.

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

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

A floating cat sanctuary on an Amsterdam canal.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

France's most famous cemetery, with some of its most curious tombs.

The gloomy ruins that inspired Bram Stoker to bring Dracula to life.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

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

An small and easily overlooked archaeology museum chock full of Egyptian artifacts.

Eighty million natural history specimens call this gargantuan museum home.

A cluttered and astounding collection of antiquities and curiosities.

The curios of pharmacist and collector Henry Wellcome.

One part local history, 99 parts gruesome haunted house.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

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

The first declared National Monument in the United States.