A Spanish town built into the cliffs.

The hidden ruins of an old hydroelectric plant reclaimed by nature.

The Roman city was the birthplace of various emperors and is home to one of the empire's most impressive architectural feats.

Hidden behind a wall, Spanish nuns distribute their signature sweets on a revolving tray.

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

An ancient Roman theatre restored to its former glory in the Spanish city of Cartegena.

The two massive guns that defended Cartagena Bay.

This portrait of Philip V is always hung upside down, in a protest three centuries in the making.

More than 2,000 species of tropical plants call this nature preserve and sanctuary home.

This legendary urban waterfall creates a dazzling display of rainbows.

These ancient sacred grounds granted amnesty to those who managed to reach them.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

At the base of Steens Mountain resides an otherworldly desert.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

The only working large-scale tea plantation in the United States.

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

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

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

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

An abandoned water sports stadium that has become a haven for graffiti and decay.

It turns out that a hurricane-prone beach is probably not the best place to house wild animals.

Located within a historic park, the beacon is the oldest standing structure in Miami.