An Australian lake whose pink hue defies scientific explanation.

A popular shrine where the Blessed Virgin allegedly appeared in 1830, displaying a holy armchair and two incorruptible remains of Lady Saints.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

An effigy of a trapped paratrooper dangles from a Normandy church to commemorate one remarkable D-Day event.

The Lone Star plaque hangs in a bombed-out bunker in Normandy to honor a Texan colonel's heroic actions on D-Day.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

Sweden's oldest animated sign is still lighting up the skyline today.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

Stockholm's deepest subway station is also a stunning ecological wonder.

Now a hotel, this former bank was the site of a robbery that spawned a psychological phenomenon.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

This enormous "cloth of the conquest" depicts the Norman invasion of England in mind-blowing detail.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

Stockholm's narrowest alley is barely over two feet wide.

A chaotic collection of coin-operated slot machines designed to delight and disturb in equal measure.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

This chimerical bridge/tunnel appears to dead end right into the sea.

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

This colorful artistic feature atop a Danish art gallery allows visitors to stroll through a rainbow.

This modernist tower was saved by a fraternity with a 500-year-old penchant for shooting at wooden parrots.

Dozens of musicians have planted trees in this Danish park, and donated songs to go with them.