Giant topiary dog once played a role in a terrorist bomb plot.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

A whimsical bridge adorned with decorative dragons.

The "dragon babies" of southeastern Europe.

This one-time health resort was used by aristocrats around the world.

This massive subterranean fissure is known as the "underground Grand Canyon."

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

A miniature train-ride through Slovenia's largest cave system.

An ancient knight and a symbol of the city's freedom.

A tiny church on a man-made island in the Adriatic.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

Bridge that died in war and was resurected.

A clock set into the concrete outside a Manhattan jeweler has been telling time underfoot for over a century.

Currently housing a corporate bank branch this building at the southern tip of Manhattan was once the gateway to luxury vacationing.

This curved Manhattan building was built to house the opulence of John D. Rockefeller's oil empire.

A bit of retro transportation flair preserved in the world's largest department store.

An artist's cute bronze subway sculptures belie his violent artistic past.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.