This natural wonder is disappearing at an alarming rate.

Hidden beneath the streets of London is a secret subway that only carried mail.

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

Hamburgers are intensely proud of their tunnel beneath the river.

The patron saint of spinsters grasps a container of dried blood.

The bears of Bern have been a city highlight for over 500 years.

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

Edinburgh's oldest statue hides within a parking lot behind the city's iconic cathedral.

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

Theme park featuring miniature replicas of European monuments.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

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

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

This giant middle finger statue sends an unambiguous message to Italy's bankers.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

This dramatic landscape hidden on the Isle of Skye looks as though you've stepped into the magical realm.

The bronze uniforms commemorate the vital role of women during World War II.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.

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

A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

The footprint of a frustrated devil in Munich's Cathedral.

Established in 1638 to battle the Black Death, this botanical garden is a treasure trove of rare flora.

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

Now famous as the "Harry Potter bridge," this impressive concrete viaduct has long been an icon in its own right.