An engineering marvel at the time of its construction, this cross-border waterway sought to connect the Black Sea to the Baltic.

Climb around the high waterfalls on series of iron ladders and bridges within the wildest gorge in the Slovak Paradise.

The ruins of a 13th-century monastery that long served as a place of refuge from wars and raids.

A gorgeous stone viaduct crosses over a bucolic valley.

A unique Holocaust memorial tells the personal stories of the Jewish residents exiled from greater Berlin.

A wunderkammer of mysterious objects and stories.

Puppet theater and museum holding a collection of more than 300.

A towering monument to war, located on a beautifully peaceful hill.

Hamburgers are intensely proud of their tunnel beneath the river.

Hamburg's first legal sex work is relegated to a gated street that still does not allow pedestrian women.

Metro station with a claim to rock n' roll fame.

Many historians today consider Sverre as Norway's greatest king of all time. 

A varied collection of brains in alcohol.

Legend says a giant, venomous spider once dwelled within this Polish church.

The "feral child" who appeared in Bavaria in the 19th century remains as much a mystery as his unsolved murder.

A former top secret nuclear fallout shelter now operates like a hotel stuck in the Cold War.

A cheeky architectural easter egg.

Europe's second largest ossuary wasn't discovered until 2001.

After years of being casually peed on by humans, this tree is peeing back.

This 8th-century Bavarian monastery is home to an exquisite Baroque-era library.

Be(w)ar(e) the moat around this historic Czech castle.

Guests become prisoners on a visit to Latvian prison.

Sculpture garden of religious statues made it through Soviet rule.

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.