Once designed as the entrance to Buckingham Palace, this structure was later relocated and stands as a victory arch.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

If you look closely at the oldest bridge in Paris, you might notice hundreds of ugly faces leering from its sides.

This 400-year-old tree is actually an immigrant from North America.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The narrowest street in Paris.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

The video game-themed street art first popped up in the French city.

This surreal statue brings a famous French novel about a supernatural cad to arresting life.

Montmartre's sole surviving windmill became an iconic landmark for 19th-century painters, artists, and bohemians.

Everyone's favorite clay duo immortalized in bronze.

This marine reptile was discovered by one of the 19th century's greatest fossil hunters.

Eighty million natural history specimens call this gargantuan museum home.

The extra platform at Gloucester Road has been used for art displays for over 25 years.

Remnants from a time before electricity.

Real bones which are said to have belonged to a Polish dragon.

An underground city of salt.

A memorial to the beloved brown bear that served in the Polish army during World War II.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

Extremely famous in his native country, this Cracovian painter is all but unknown beyond Polish borders.

Learn the fine art of making a centuries-old treat at this hands-on food museum.

Protecting the dead from opportunistic body snatchers.

A famous pilgrimage site that remains hidden in the midst of a city.

The statue honors a beloved bird that once roamed St. George's Market.