Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

The final resting place of the great navigator, or maybe his brother.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

The castle where Martin Luther secretly translated the New Testament from Greek to German while in hiding.

A century-old shot ball factory tower is open to the public once a year.

Every hour the doors open to reenact the legend of the heroic mayor who saved his town by drinking a gallon of wine.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

These bronze pamphlets remember a remarkable group of Germans who fearlessly opposed the Nazis in the very center of their power.

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

Skeletons dressed in extravagant 18th century royal costumes cavort in the aisles of this German basilica.

The fairy tale castle of the "fairy-tale king."

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

An exotic reptile facility showcasing some of the rarest, most venomous snakes in the world.

The only remaining place where you can play this century-old game for cash.

The world's largest piece of copyrighted artwork.

The nation's second-ever First Lady urged the founding fathers to "remember the ladies."

The hill that gave the Massachusett tribe, and later the state, its name.

This bridge was the birthplace of a unit of measurement based on a fraternity joke.

An interesting decoration on this historic site, this weathervane comes with as many legends as it does questions.

Each August, one of the largest religious (and food) celebrations in the country is held in Boston.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

On a former island, this old fortification once used to protect the Boston Area and started Edgar Allan Poe in his military career.

The massive machine creates cracking displays of indoor lightning.