This 15th-century island fortress later served as home to the executioners no one wanted to live near.

The construction of a tram line unveiled hidden remnants of the old medieval city.

An imposing Omani fortress surrounded by date palm trees.

A former Nazi lookout tower with a magnificent view of the Rhineland.

A slightly surreal menagerie of structures that were lovingly spared from demolition and reconstructed in a field.

The storied English village that pretended to be insane inspired NYC's nickname and the fictional namesake in the DC Comics universe.

Crumbling ruins of the thermal baths that once attracted royals and aristocrats from throughout Europe.

The profile of one ill-fated deacon was emblazoned forever on this church window during the Halifax explosion.

Bloodstains can still be seen in this medieval church where two medics saved lives on D-Day.

The writer took refuge in this home in Southern France for the last 17 years of his life.

This spectacular public market has got meat, fish, vegetables, baked goods, and enough kielbasa for a lifetime.

The oldest Buddhist monastery in Mongolia has survived centuries of invasions, political shifts, and religious purges.

A completely round house designed for the Atomic Age.

A whimsical sensor instrument for Minneapolitans to play on their walks to work.

A mysterious monument where a woman who records say never existed was burnt alive for being a witch.

A Christian retreat founded to welcome refugees fleeing from the Nazis during World War II.

This chain of artificial lakes was an ideal test ground for the aircraft that would carry the "bouncing bombs" used by the WWII "Dambusters" squad.

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

The world's oldest Jewish library was founded by Sephardic Jews in 17th century Amsterdam.

The preserved arm of a third-century sorcerer is believed to have the power to lift curses and spells.

For 150 years one family has been producing the iconic hot sauce on a bayou island made of salt.

Literal "money laundering."

Statues of Ramona Quimby, Henry Huggins, and Ribsy the dog in the park where their adventures "really happened."

This lake in northwest Iran has started turning from green to red more frequently than scientists are comfortable with.