The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

A subterranean shelter remains intact under a busy Paris railway station.

Touching the iron railings of Tarragona's balcony to the Mediterranean is said to bring good luck.

Long tunnels run under the ancient chariot racing circuit to the tower.

This Roman arena once played host to bloody gladiatorial battles.

Bullet holes in the church wall are a reminder of the violence that followed the assassination of a high-ranking Nazi officer.

Increasingly decayed figures stand as a powerful reminder of the human costs of Czech Communism.

A series of playful yellow penguins share a serious message about the environment.

The tunnel's elegant proportions keep you snug with no claustrophobia freak-out.

Walk through Czech history in Prague's largest graveyard.

Mummified monks and the accidentally interred, in a 17th-century crypt.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

This bronze statue of Martin Luther King was placed in the park without permission.

The ruins of a medieval castle that once belonged to one of the most powerful families in the Netherlands.

A UFO-shaped event building originally intended to be a science museum showcasing the future.

This miniature take on the Kremlin is one Dutch man's retirement project.

A dream-like maze full of strange art, surreal spaces, and fantasy landscapes to get lost in.

A market built atop boats is one of the few floating holiday markets in Europe.

This beautifully designed star-shaped fort was the premier defense system of the late 1500s.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

This massive mural by famed pop-artist Keith Haring was hidden for almost 30 years until its 2018 rediscovery.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

Colorful and chaotic stacked hotel in North Holland.