A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

This elaborate towering structure was once famed for its revolutionary height.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

Decades before the scandal, this staircase on the river was a literal "water gate."

Washington's iconic carousel has a nice piece of Civil Rights history.

An overlooked memorial honoring the local Washington residents who died in World War I.

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.

Look closely and you’ll notice that the color changes a third of the way up the tower.

The word "Watergate" will forever be associated with the infamous scandal in 1972, but this fountain is famous in its own right.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

Where the U.S. government kept its actual treasure, before Fort Knox.

At least according to the Guinness World Records.

The highest peak in mainland Spain is said to be the final resting place of a Muslim king.

This abandoned, turn-of-the-century astronomy hub is now the subject of more photographs than it ever took.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

One of the most spectacular bridges in Spain spans a narrow chasm that divides the city of Ronda.

Single runway interrupted by a busy road that cuts across its middle.

There was a top secret plan during World War II to seal a group of soldiers inside the rock.

Red, white, and blue painted steps along with a Union Jack celebrate the outcome of Gibraltar's 1967 referendum.

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

The world's largest wooden structure.

The defensive tower was built centuries ago to warn locals of Berber pirate attacks.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

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