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

This poured-concrete water reservoir is a gem of modernist architecture well-hidden in a city forest.

The internet as provided by a James Bond villain.

A Japanese video game arcade hides in the back of a Swedish pool hall.

Dine on food tied to Viking history and legend at this subterranean Stockholm spot.

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

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

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.

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

Two planes stand abandoned after the closure of an aircraft-themed restaurant.

This truly palatial work of Communist-era architecture now sits crumbling on a Croatian beach.

This Croatian computer club features such gaming relics as the infamous Virtual Boy and an 8-bit Pacman machine.

A self-proclaimed libertarian micro-state on a tiny bit of disputed territory between Serbia and Croatia.

Croatia's towering concrete blossom grows from the site of a World War II concentration camp.

This picturesque medieval monastery guards a small trove of historic treasures.

This huge metal monument is slowly being stripped to its concrete skeleton.

The remains of a sunken military ship wreck visible through clear water.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

An ethereal glowing blue ocean cave in Croatia.

The vast chamber inside this abandoned cooling tower looks like something out of a sci-fi dystopia.

Dedicated to the American general whose reply to a German demand for surrender was simply "Nuts!"

Take a leisurely walk through the park to find the seven giant troll sculptures hidden throughout the park.

In the shadow of a former battleground, the resting place for nearly 2,000 soldiers who died in World War I.