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

It was meant to help transport wounded soldiers to a secret underground hospital.

Locals rallied to save this beloved mural after someone mistakenly attempted to cover it.

The remains of Alfred Nobel's first nitroglycerine factory can still be found on the shores of a Swedish bay.

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

A tombstone on the grounds of the royal castle marks the burial site of a Swedish king's beloved dog.

This 2,000-year-old stone maze is one of the oldest in the country, but its purpose is still a mystery.

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

This museum of Viking vessels allows visitors to take a replica out for a spin.

This patch of land is home to Sweden's largest burial mound, allegedly belonging to a mythical king.

This runestone once destroyed by an explosion has been painstakingly reassembled to save its history.

Unfortunately, you can no longer spend a night in this single-person treetop hotel.

Stone carvings record the Norse myth of Sigurd, providing a glimpse into Scandinavia's transition from paganism to Christianity.

A floating underwater hotel, created by a Swedish artist.

One of the world's oldest continuously operating meteorological stations sits on a hill in Stockholm.

This Stockholm light tower can be controlled by anyone with a smartphone.

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

This hotel was once home to a steamliner company and became the final rest stop for Europeans heading to the New World.

Inside this metro station is a section of the city's former medieval fortification.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

Albert Einstein would often sit in this chair during visits to the observatory to discuss science with Willem de Sitter.

This replica of Columbus's famous ship houses the history of La Palma's maritime importance during the Age of Exploration.

A former 16th-century monastery houses a museum dedicated to the island and its culture.

The suspected burial mound of legendary Viking Björn Ironside.