For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.

A lush indoor jungle fills this bustling Madrid transportation hub.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

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.

Historic Hull Street was actually the first street with a proper name in the Boston area.

The site where Charles Dickens gave his first public reading of "A Christmas Carol" in the US.

An easy-to-miss garden in Boston's North End honors the mother of JFK and others who lost children in WWII.

This massive tea kettle was once a promotional stunt for the Oriental Teashop.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

Ice cream stand, snack bar, and time capsule of milk conveyance.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

The oldest Italian café in Boston, this spot also serves as a veritable museum of vintage coffee ephemera.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

Baroque celebration of the end of the Great Plague of Vienna.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

Two large eyes painted anonymously on a mountain overlooking the city pay homage to an old legend.

Skulls and skeletons are omnipresent in this church dedicated to souls trapped in purgatory.

People have been living in the cave houses on this Italian hillside since the Neolithic era.

This influential Renaissance-era library was once the haunt of kings and monks.