This Neapolitan exhibition hall grants weird and wonderful insight into the intricacies of human biology.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

This magical-looking island is notorious for the misfortunes suffered by its owners.

Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

Beautiful antiques and obscure engineering artifacts trace the evolution of phones from rare luxuries to ubiquitous.

Legions of Roman soldiers bathed in this ancient spa complex under a Budapest transit station.

A forgotten graveyard lost in the tangles of an overgrown garden.

This hidden art nouveau gem was designed by an architect in search of a national style.

A Hungarian pharmacy museum with a box full of mummy powder.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

A former squatter's paradise outside Prague.

The palace window through which Protestant nobles flung two Catholic regents, thus sparking the Thirty Years' War.

What looks like a crashed Zeppelin is actually a bright, airy reading room perched atop a modern museum.

This doorless 20th-century elevator doesn't stop or slow down.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

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