It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

Small Easter eggs are hidden in the ventilation holes of the city's newest trains.

There are hidden patterns on the subway seats of some Stockholm metro cars.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Stockholm's narrowest alley is barely over two feet wide.

Stockholm's tiniest statue is of a small boy looking at the Moon.

Hidden in plain sight, Sweden's official ordnance datum is now abandoned.

Stockholm's deepest subway station is also a stunning ecological wonder.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

This statue and park honor the Swedish chemist Jacob Berzelius, one of the founders of modern chemistry.

A heated statue pays tribute to one of Sweden's great actresses.

Several cannonballs of mysterious origins decorate two buildings in Stortoget's main square.

A 130-year-old urinal is the oldest of Stockholm and perhaps all of Sweden.

This small museum nestled inside a souvenir shop is dedicated to Sweden's most well-known toy.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

Now a hotel, this former bank was the site of a robbery that spawned a psychological phenomenon.

Finally reunited, the three effigies now stand in a museum courtyard.

It houses the remains of a 17th-century version of the Titanic.

A former suicide bridge is now accumulating symbols of love instead of a body count.

A steel paper plane is all that remains of a crashed aircraft that caused an amazingly small amount of damage.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

This roadside shrine to an unofficial saint has welcomed the wishes and prayers of local believers for generations.

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

Abbey built on the ruins of Roman catacombs.