In North Wales a secret facility which once manufactured mustard gas and enriched uranium lies in ruins. In Malta is a luxurious quarantine facility, that hides a dark secret.

Bizarrely-shaped huts in India, once home to global superstars, are now eerily quiet and neglected, and a shattered compound in Colombia linked to a criminal mastermind.

Ruins of a vast industrial ghost town in the United States, a windswept Scottish island and the remains of a resort in Japan that watched a city burn.

A fairy-tale castle that staged one of the strangest stories of the Second World War and a haunting complex on an old American Frontier.

Legendary film sets with surprising pasts and real locations that inspired Hollywood. Within these decaying structures are the echoes of history.

An engineering masterpiece carved into the cliff-face, and a long-range beacon that transmitted one of the most infamous messages in American history.

A volcanic island just off Taiwan containing chilling ruins from its darkest era, and a miniature railway that lies forgotten in the woods of Arkansas.

A real-life concrete jungle in America's 'Rust Belt', and an industrial facility that brought energy to a remote corner of the world.

An iron monster lost in the Alaskan tundra, a Crusader fort thrown into a modern conflict, and a prison built to house a mafia kingpin.

An American desert canyon where fortunes were made and lives were lost, and an island fortress in Scotland with an Achilles heel.

A Middle Eastern region littered with ruins and a strange facility in Taiwan that struck fear into the hearts of those who knew its true purpose.

Eerie ruins hiding in the forested hills of Arkansas, USA, and a disintegrating gulag in Albania that housed enemies of the state.