Tiring of digging out the door to this church for every service, it was eventually abandoned to the sands.

Mounds, rune stones, and a 1,000-year-old church, left behind by Denmark's first two kings.

A stunning gilt bronze relief denounced by Hitler as "degenerate art"—even though it was dedicated to the Nazi leader.

Böttcherstraße's bells, extolling Nordic virtues and the great conquerors of the world.

Constructed by forced laborers, this submarine pen is now a museum and war memorial.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

Mysterious texts covered in mystical symbols were found in caves at this site centuries ago.

A unique seaside cave where Aleister Crowley faked his own death.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

The facade of this 16th-century building is decorated with carvings of 300 seashells.

Cliffside houses provide a spectacular view from their perch above the valley.

This place bears witness to the loss of many lives during WWII, and stands in stark contrast to the American Cemetery.

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

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

Malmö’s bronze prince yearns for Copenhagen's 'Little Mermaid'—and his missing crown jewels.

The only surviving leech house in the United Kingdom was a home for bloodsucking worms until the 1900s.

This Moorish fortress has guarded Málaga from the slopes of Gibralfaro hill for nearly a thousand years.

A granite plane marks the site where a French aviator completed the first airplane flight across the English channel.

This building from the Middle Ages was dedicated to the patron saint of Norway.

An intriguing three-sided folly is a testament to one man's devotion to Catholicism and the number three.

The intended purpose of this unfinished Elizabethan building remains a mystery.

The sanctuary seems to either float atop the water or sink into the dirt, depending on the water level.

Isaac Newton's former home, where the famous apple tree still stands.

In the U.K., a historic workhouse shines a light on the early, harsh treatment of the poor.