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

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

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

Sweden's "good old days" painstakingly re-created in a model village.

Bring your hiking shoes, wool socks, and thermal underwear for a stay in these cozy forest huts.

The world's first ice hotel is still one of the most elaborate and beautiful.

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

A series of modernist treehouse hotel rooms grace the outskirts of an Arctic forest.

From Coke II to Google Glass, this exhibit features some of the most spectacular commercial flops.

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

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

A forest park outside Tallinn full of architectural and artistic curiosities.

Wars fought and wars won are remembered by these abandoned bunker ruins.

This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

This Soviet-era "closed town" was a top secret uranium producer often left off of maps.

Estonia's largest creative city is a vibrant bohemian hub located within a former industrial complex.

The gutted remains of this Estonian mansion are a monument to a tragic love.

Mysterious craters may have been home to an ancient cult.

A small island dotted with old, historic Finnish buildings.

Extraordinary animals sculpted from leftover junk.

No matter how many times this community-run sauna gets destroyed, it always rises from the ashes.

The church's remarkable frescoes incorporate Finnish artist Hugh Simberg's trademark themes of death and the supernatural.

The etchings on this narrow channel between two islands bear witness to maritime travelers who have passed through since the Middle Ages.

This disused church, left to the elements of the Arctic Circle's forests is open for exploration.