This bike path was sunk below water level for maximum wonder.

Building Men of War and Indiamen from Holland's Golden Age.

While most bridges allow roads to pass over water, this one allows water to pass over a road.

Modern commuters still pass through this 2,000-year-old Roman archway.

A distinctive former power plant turned university lecture hall looks like it could make you breakfast.

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

A luxury hotel housed in a former 15th century Gothic church.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

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

Incredible labyrinth of man made caves.

Sculpture designed by Turkish artist and professor Mehmet Ali Uysal.

Descend into the tunnels to experience the life of a coal miner.

A Belgian self-built tower inspired by the Bible and ancient civilizations.

This sprawling Belgian fort was once thought of as impenetrable but now it is simply an abandoned relic.

A beautiful maze marks where three countries meet.

What was once a bustling mining installation is now a bustling hub of contemporary art.

This towering church is home to a world-famous organ and a treasure trove of medieval art.

Originally envisioned by King Ludwig II to rival Versailles, Herrenchiemsee's "New Palace" remains half-gilded for lack of funds.

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”

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

The prototype for all Nazi concentration camps.

Four-story slides send people whizzing through the math department at this Munich university.

An abandoned train station in Munich constructed for the 1972 Olympic games.

Golden cobblestones remember a time when this small alley was used to avoid having to give a Nazi salute.