Eco-friendly island mansion.

A tiny, picturesque island, where cows and wild horses wander around the houses.

Relics of Australia's convict past, and a modern scene of unimaginable horror.

An abandoned guano-mining city in the South Pacific.

The first island in the world designated a light-pollution-free astronomical observation point.

Cockatoo Island is a Heritage-listed island in the middle of Sydney Harbour.

The former Naval shipyard is open for exploring - mostly.

Two islands just 4 km apart separated by an International Border and Date Line.

The coldest city in the world.

Monastery, army base, and infamous Soviet Gulag in the far Russian north.

Military and first responders can test their skills in a Foggy Bottom mock station down in Georgia.

Museum design and public transportation meet in this unique Russian train car.

Specimens collected by the author of "Lolita" and self-taught lepidopterist are exhibited in his childhood home.

The villagers of the coldest inhabited place on Earth adjust to unique challenges presented by day-to-day living.

The cell which saved the life of Ludger Sylbaris, "the man who lived through Doomsday."

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

An obscure public service from the U.S. government that redeems burnt, moldy, and soiled old greenbacks.

Stalin's prisoner-built rail line sits in ruin, never having a single car ride its tracks.

Built to hold the worst of the worst of the Nazi war prisoners.

Bits and pieces from the ill-fated Donner Party's winter cabins.

Frida Kahlo's childhood home, now a museum of her life and works.

An island filled with hundreds of hanging, decomposing, decapitated dolls.

This family tattoo parlor has been inking religious pilgrims in the Middle East for 700 years.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.