A mansion where wonders of Christmas are celebrated all year long.

The largest brick bridge in the world.

This historical Netherlands fortress still bears the marks of its single siege.

A once-magnificent collegiate church is falling into ruin.

A staggering collection of satellite models and actual flight parts.

The idyllic island where the philosopher Jean-Jacques Rousseau spent “the happiest time of his life.”

This unique Renaissance castle was turned into a home for Nazi occultism.

This futuristic German television spire is actually the world's largest digital clock.

Twisted buildings adorn the banks of the Rhine river.

A beautiful maze marks where three countries meet.

This striking fort on the Maginot Line looks just as it did after being destroyed in the Fall of France.

A memorial to the soldiers who died in the bloody battles to control Verdun in World War I.

A preserved Nazi labor camp now has a Holocaust museum on site and memorials to the thousands that died while imprisoned at the camp.

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

This beautiful 19th-century temple stands atop the ruins of its predecessor.

A small but immensely extravagant palace built by the "Night King."

The oldest surviving wooden bridge over Rhine lets travelers cross easily from Switzerland to Liechtensten.

The prototype for all Nazi concentration camps.

In one of the world's smallest countries, a royal's personal winery is open to the public.

This 170-year-old Swiss guesthouse built into the side of a mountain is best accessed by a cable car.

A graveyard and memorial chapel for victims of leprosy.

The prison where Hitler wrote "Mein Kampf," and 278 Nazis were later executed for war crimes.

Obscured within a ring of trees, this abandoned World War II relic hides on a German hillside.

Thousands of flowers create enchanting pink tunnels over the city streets.