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

Stockholm's last remaining paternoster elevator.

No one knows who's responsible for decorating this tunnel with stuffed animals, but the people love it enough to protest their removal.

A hidden bathhouse in one of Stockholm's oldest and busiest neighborhoods is open to anyone who can find it.

Sweden's first nuclear reactor, R1, can be visited 25 meters underground.

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

An illuminated manuscript comprising the life's work of a lone monk, inexplicably decorated with a portrait of Satan himself.

Sound travels strangely in this underground whispering gallery.

Museum on earth sciences featuring a recreation of a famous curiosity cabinet.

The final resting place of the author who gave us the Little Mermaid, the Ugly Duckling, and many more beloved fairy tales.

An artist's mausoleum with a haunting echo.

In downtown Oslo, a menacing and terrifying relief clings to a church wall.

Thousands of miniature bronze sculptures have taken over this city square creating a unique art installation.

An "evil painter" included pointed symbols in this artwork to poke fun at members of the Danish Parliament.

This bridge's unique architecture honors nautical heritage and encourages self-awareness.

The gilded, masterful astronomical clock will calculate time, dates, and planetary positions for thousands of years to come.

Once a meeting point for great thinkers, and the midpoint of the country.

A former smithy turned cultural hub with the capital's largest mural space.

Beneath Denmark's Højbro bridge, a bronze merman and his seven sons forever mourn for the mother and wife who left them for land.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

Devious political maneuvering and four ancient, working telescopes are central to the world's second-oldest observatory.

Visit the ancient, mysterious Roman catacombs ... in the Netherlands.

This historical Netherlands fortress still bears the marks of its single siege.