The great Danube river starts here.

The unexpectedly beloved remnants of a controversial thermal power plant.

The lost Latin words were reconstructed using the holes from the nails that once pinned them in place.

The Polish capital has had a deep connection to its guardian mermaid for almost a millennium now.

In Florence's great Duomo, a 26 foot fresco honors a mercenary famous for attacking Florence.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

The oldest operating pharmacy in the world features 800-year-old recipes.

A lush indoor jungle fills this bustling Madrid transportation hub.

Memorializing the bravery of one young woman facing the monster of her age.

The modern birthplace of Irish freedom.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

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

The site of the first medieval crusade that pitted Christians against Christians.

A historic Christian shrine nestled within a spectacular natural cave.

A rather vulgar example of the transition from Latin to the Italian vernacular.

Barça football fans might see the insignia hidden in a church window as a divine sign.

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

The world's largest solar furnace uses 10,000 mirrors to concentrate the sun's rays to generate power.