Home to three historic ships from the age of Vikings.

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

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

A man has revenged his true love's betrayal through tears and stone genitalia.

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.

The library's graceful rotunda is like a bibliophile's temple.

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

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

This secluded walkway overlooks a magnificently wild London green space.

Remnants of cells from the most notorious London prison may lie in the basement of a rare Victorian Gin Palace.

A historic arboretum and non-conformist, non-denominational park cemetery.

A closed London rail station created to cart away the dead still bears the marks of attempts to make it less morbid.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

The sixth of London's "Magnificent Seven" cemeteries, and a source of unlikely inspiration to Beatrix Potter.

Scattered throughout London are ancient remnants of the city's former bounding wall.

A historic London cemetery now serves as a nature park incorporating gravestones & memorial statues.

This hidden green space is the city's second largest conservatory.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

In this cobwebbed old operating theater, you can practically hear the screams of the unanesthetized patients.

An incarceration museum on the spot of possibly the oldest prison in England.

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

Rebuilt remains of a temple to Roman god Mithras.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

This South London cemetery holds the remains of more than 15,000 people.