The remains of a convent turned military barrack in the heart of Madrid.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

The ruins of a 2,000-year-old Roman fishing village perched on one of the best beaches in Spain.

These "mermaids" that surround a plaza in Segovia are rather sphinx-like.

Climb inside an iron crystal magnified 165 billion times its normal size.

A largely overlooked statue that may commemorate the first publication of 'Don Quixote' outside of Spain.

This cannonball has been lodged in the church wall since a 1695 bombardment destroyed the city center.

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

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

Unable to build support structures on glaciers, the engineers for this tramway were forced to design a unique system.

Spitfire airplanes with butterfly wings hover over Prague’s skyline.

A grumpy old water goblin guarding an old mill on the Devil’s Stream in Prague.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

Local folklore claims that this wall was not built for defense, but to provide labor during a time of famine.

A Baroque mansion with ties to legendary magicians and alchemists.

This spooky statue sits outside a famous Prague theater.

Macabre astrological automaton clock dating to the late 1400s.

Countless grotesque faces stare out from this eerie Prague art wall.

The statue of a cursed knight is said to come to life every 100 years.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Along the edge of this fountain are 365 smaller fountains that represent the days of the year.

Follow the original medieval paths that wind through this intriguing section of the city.

This network of narrow, medieval passages has the most delightful name.

This tree was grafted from the actual tree that led Isaac Newton to ponder the theory of gravity.