Disused seaplane hangar gets a second life as the jaw-dropping home of Estonia's museum of maritime history.

This set of concrete chambers resonates according to different notes of octaves.

This free museum is building a collection of books that are banned, censored or burnt around the world.

The oldest continuously operating pharmacy in Europe.

Take a seat and hear a song by the composer Frédéric Chopin.

A large boulder was declared a local landmark by a popular vlogger.

A series of concentric circles represented a bold new experiment in socialist urban planning, and it notoriously difficult to get around.

Rusted cars, trucks, and buses form a fascinating collection of Soviet-era machinery.

Mysterious craters may have been home to an ancient cult.

This abandoned fighter jet launch center is now a haunting street racing course.

This abandoned office building is a lasting example of Soviet-era architecture.

Atop this electronic store resides a massive fighter jet.

This insurance company building reminds customers that witches, bears, and gnomes are out there, best be insured.

Architecturally stunning library serves as the hub of Finnish scholarly life and culture.

An abstract monument to a symphonic composer.

Absolutely no saxophones in the library.

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

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

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

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.

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

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

A golden egg-shaped sauna in the Arctic tundra.

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