This World War II-era bunker hides between medieval chapels in Nijmegen's city center.

The oldest skyscraper of Europe now stands dwarfed by the surrounding structures.

How one woman gave orphaned sculptures a new home in the city of Utrecht.

The only bicycle museum in the Netherlands charts the invention of the now-ubiquitous two-wheeled machine.

The mirrored section takes the shape of Hebrew characters when viewed from above.

One man's remarkable private collection of art from around the world.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A small but charming botanical garden that contains many exotic plant species.

This may be the world's only drive-through windmill.

A replica of the Roman emperor in glorious full color.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

This castle has links to Portugal’s founding and struggles for independence.

This historic streetcar system has been running since the 19th-century.

Elaborate tile work in this railway station tells the story of Portugal.

A hidden three-foot-wide house separates these two regal churches.

The world's largest reflecting pool is just two centimeters deep.

This park built on a former fortress has a reputation for romance.

This large open-air museum showcases the ordinary lives of the people of the Netherlands and pre-industrial crafts and practices.

The cutest way to stay safe in traffic.

A uniquely preserved neo-Gothic church that is now home to a collection of art and woodcarvings.

The oldest statue in the Netherlands has survived relocation, bombardment, and burial.

A secluded art gallery hidden within the cellars beneath Tallinn’s medieval monastery.