A prehistoric geological oddity tucked behind Stockholm's natural history museum.

Part of an abandoned19th-century fortress hides in plain sight inside a modern office building.

A traveling Bronze Age sacrificial stone that was used to honor elves, fairies, and other woodland spirits.

What looks like a birch tree smushed between two pieces of glass often confounds commuters.

Tucked away in a downtown Stockholm park are the remains of a World War II defense position.

Twice a year, this floating library delivers thousands of books to the remote islands of Stockholm’s archipelago.

The final resting place of the man whose name has become synonymous with greatness.

This railroad track was so secretive that it was omitted from all maps.

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

Inside this church, a monument honors the first burial site of the famed philosopher.

An ancient tree that was once the favorite of a young Swedish royal.

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

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

A Stockholm metro station is home to an escalator that is not only the longest in Sweden, but among the longest in the world.

Enormous ants wielding giant pine needles guard a Stockholm real estate company's office.

This giant crucifix is like U2's Joshua Tree for Swedish death metal fans.

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

A golden plaque marks the site of the mysterious unsolved assassination of the former Swedish prime minister.

The scars of a remarkably organized public protest to save 13 elm trees are still visible in this Stockholm park.

A 12th-century church with a medieval fresco and an intriguing “Greek runestone.”

An 11th-century runestone decorates the halls of Terminal 2 of this Scandinavian travel hub.

A plaque marks the house in Stockholm where the French philosopher René Descartes lived up until his death.

The single richest source of elemental discoveries in the world.

Located in an old church, this brewery produces a different kind of holy water.