The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

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

An existential riddle in the world's largest ancient castle.

A saintly relic hidden in a Prague church basement.

A massive, abstract lookout tower providing a panoramic view of Prague.

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

The tunnel's elegant proportions keep you snug with no claustrophobia freak-out.

A 400-year-old mummified arm dangles from the ceiling of St. James the Greater, serving as a warning to thieves.

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

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

The first museum in the world devoted to sexual gadgetry.

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

The hidden lair of an alchemist rediscovered in a 2002 flood.

Armenian monks at an island monastery in the Venetian Lagoon make a rare rose petal jam.

The oldest of Venice's plague quarantine stations, designed to keep the medieval city safe from disease.

The only museum with its curator—and her pets—buried inside.

Originally a leper colony, the island is now an Armenian monastery that's home to an incredible manuscript library and eclectic museum.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

This abandoned island off the Venetian coast has been a radical monastery, a political prison, and a secret Nazi base.

The marble facade hides a little-known medical museum with early surgical instruments and rare copies of canonical texts.

The plague quarantine island home to the alleged "Vampire of Venice."

Venice's "Island of the Mad."

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

At this bohemian accommodation, guests who dream of joining the circus can spend the night in themed wagons.