These 90-year-old murals of local kings, Vikings, and outlaws hide in plain sight in a beautifully baroque shopping arcade.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

These hut foundations are believed to be the residence of Romulus, founder of Rome.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

The former home of a mad diplomat is said to still be marked in bloody, arcane scrawls.

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

This museum inside Amsterdam's largest cemetery explores how people deal with death.

A Portuguese Jewish cemetery filled with stunning grave monuments that date back to 1614.

One of the oldest structures in Helsinki is this burrow grave that dates back to the Bronze Age.

The door to the museum holds a unique artifact from the Finnish Civil War.

A medieval setting reimagined into a unique art alley.

This handsomely carved wooden church is more than 800 years old.

Moss and stone turn this waterfall into an otherworldly liquid veil.

Nine centuries-old fortresses guard the walls of this medieval Romanian city.

The tiny, studious rodents greet visitors to the National Archives of Finland.

Largely overlooked, this little fountain on Museum Island is a whimsical tribute to a Prussian king nicknamed the “Fatty Flounder.”

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

A quirky Poe-themed joint on an island keen to celebrate its overlooked connection to the famous writer.

This fairy tale forest hides scenes from some of the more obscure and bizarre Western nursery stories.

Where once there was a train station bathroom, there is now this German burger joint.

The Boston square dedicated to the dark poet who was born nearby.

An eerie reminder to the horrors of World War II.

This small memorial honors a ferocious feline and local hero.