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

An eerie, existential museum dedicated to the author of "The Metamorphosis."

A collection of anatomical samples from one of the first anthropologists to suggest that humans reached North America by crossing the Bering Strait.

This artificial cave looks like something out of a fairytale.

Macabre astrological automaton clock dating to the late 1400s.

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

Walk through Czech history in Prague's largest graveyard.

Two stunning 17th-century libraries and a cabinet of curiosities.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

This hidden art nouveau gem was designed by an architect in search of a national style.

Tucked away near more famous landmarks lies a statue meant to symbolize the confluence and continuing development of human culture.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

The romantic garden was the epicenter of the Hungarian art scene in the 1880s.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

This unattributed sculpture in Amsterdam is hiding in plain sight.

Famed for its pie, this eatery has a hidden tunnel that allowed Catholics to secretly walk to church during the Reformation.

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

A beautifully eclectic mix of architectural styles.

The history and future of cannabis.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

Seven mini rowhouses fill the gap between 54 and 70 Westerstraat.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.