Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

The site where one of the most famous poems of World War I was composed is preserved to honor the legacy of the work.

In the shadow of a former battleground, the resting place for nearly 2,000 soldiers who died in World War I.

A rare example of World War I trenches from the British front.

A moving memorial to the fallen and missing from WWI trenches.

This memorial museum chronicles the apocalyptic destruction of the First World War.

The compass on its front was a handy tool for 17th-century merchants who needed to know the direction of the wind.

Inside this former medieval prison is a collection of objects designed to inflict unbelievable pain and suffering on the human body and mind.

Christ's blood allegedly preserved in a Belgian town.

Theme park featuring miniature replicas of European monuments.

Climb inside an iron crystal magnified 165 billion times its normal size.

A little sculpture with a large wardrobe.

The final resting place for the remains of 143 Habsburg royalty.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

This skeleton-filled altar piece served as a backdrop to one of the most iconic scenes in "The Sound of Music."

The amazing wonder cabinets of a very rich Austrian archbishop.

Trick water gardens from 1619 featuring a 200 piece mechanical theater powered by water.

A public urinal so pretty, it was declared a national monument.

One of Amsterdam's narrowest houses is located right across the canal from its widest.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

Now a museum, this building was once a 14th-century monastery and the place where the founder of the Dutch nation lived and was assassinated.

The ruins of this Dutch castle sit atop a labyrinth of once-secret tunnels and passageways, dating back over 900 years.

Visit the ancient, mysterious Roman catacombs ... in the Netherlands.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.