This Arabesque Italian castle was built with a primitive, if ingenious, air-conditioning system.

This skeletal, unfinished Gothic church once housed a miraculous masterpiece by Raphael.

The forbidden island of the Tuscan Archipelago may still contain buried treasure.

This triumphal 16th-century arched gateway leads to the oldest street in Palermo.

A whale rib was used to advertise the store by the arch that offered exotic goods from far away.

Legend has it this fountain built to symbolize the Pope’s power hides a strange secret concerning Neptune's manliness.

Centuries ago, red and white wine poured from the statue's breasts whenever a new Venetian ruler was elected.

Cave shrine on Monte Pellegrino.

Every inch of this chapel is covered in craftsmanship from across the world.

An open-air museum in a mountain valley features works designed to blend in with—and disintegrate back into—their natural surroundings.

Europe’s oldest natural human mummy.

This mosaic-lined medieval church was built by the world's first admiral and still holds mass in ancient Greek.

Romans built the world's tallest artificial waterfall in 271 BC.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Pilgrimage site for star-crossed lovers.

Crushed coral and crystals give the sand its signature coloration.

Go inside to really appreciate this 500-year-old technological masterpiece.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

A stunning architectural yet functional feat, towering over Oslo.

Catch a scenic view of Warsaw's Old Town from the top of a centuries-old dumping ground.

A collection of modern and vintage pinball machines housed in the cellar of a 15th-century building.

These 18th-century paintings of Warsaw were used to reconstruct the city after World War II.

This picturesque castle in Poland has a rich history, including a legend that ties it to lost Incan treasures.