Old Danish castle immortalized in Shakespeare's Hamlet.

Beneath the impressive baroque cathedral that rises from the center of Berlin lies the largest collection of Prussian royals in the world.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

France's most famous cemetery, with some of its most curious tombs.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

The approximate spot where the last Grand Master of the Knights Templar was put to death.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The ship built to ferry passengers and goods to the doomed Titanic is now the last remaining White Star Line vessel.

A museum marks and documents the site of the Titanic's launch.

The atmospheric road was never meant to be so creepy.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.

Northern Ireland's Brobdingnagian stepping stones.

A solemn memorial in a majestic setting that honors a 1692 tragedy.

From here, the loch appears to take the shape of mainland Scotland.

Now famous as the "Harry Potter bridge," this impressive concrete viaduct has long been an icon in its own right.

A close look reveals that the Scottish monument is just slightly off-kilter.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.