A miniature city, once ruled by the Queen of the Netherlands.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

A preserved building where the dead were once watched for signs of life.

A Portuguese Jewish cemetery filled with stunning grave monuments that date back to 1614.

Deceased nuns were placed on stone chairs to decompose, while the surviving nuns prayed near the lifeless bodies.

The largest bell in the world has been swinging high above a Cologne cathedral for almost a century.

This small condiment museum makes all manner of mustards with a 200-year-old mill.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

This cheese shop also houses a museum devoted to Dutch dairy.

Tucked in the back of a flower shop, its collection details the fascinating history of the Netherlands's iconic symbol.

Amsterdam's former hotspot for public executions and dissections.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

A maze of crosses marks the jumbled divide between the Netherlands and Belgium.

One of the largest burial mounds in the Netherlands and Belgium.

Ever hear of the Milazzo Cage?

A wunderkammer of curious objects and intriguing art nestled within a hub of ancient Roman sites.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

This subterranean shrine beneath a bike rental store celebrates the iconic Italian scooter.

One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

One of the most important yet well-hidden museums dedicated to the history of medicine.

An enigmatic modern marker left next to a historic Roman site.

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

This former Roman Catholic Church still contains the embalmed hearts and organs of 22 popes.

A collection of objects supposedly singed by the hands of souls in purgatory.