The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Budapest's Communist-era statues, banished to the suburbs.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Copenhagen's celebrated theme park and gardens.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

This small Bavarian graveyard is filled with empty graves for German soldiers lost during the World Wars.

A memorial for a young woman and her ghost, which are claimed to have caused countless deathly shipwrecks.

Tiny castle in the middle of the Rhine made you pay to pass.

Each year, Germany's "City of Dragons" slays the world's largest walking robot.

A Black Forest cuckoo clock theme park features one timepiece big enough to walk inside.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

The prototype for all Nazi concentration camps.

A striking 12th-century-style castle built on the edge of a cliff.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

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

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

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

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

Macabre astrological automaton clock dating to the late 1400s.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.