Abandoned Engineering

Stalin's Subway: 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. S7 Ep2

Disaster at the Maya Hotel: 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.

Murder Underground: An engineering masterpiece carved into the cliff-face, and a long-range beacon that transmitted one of the most infamous messages in American history. S7 Ep4

Murder Underground: An engineering masterpiece carved into the cliff-face, and a long-range beacon that transmitted one of the most infamous messages in American history. S7 Ep4

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

The Mafia Bunker: 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. S7 Ep6

The Mafia Bunker: 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. S7 Ep6

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

Inside Man: A Middle Eastern region littered with ruins was the site of an extraordinary deception, and a strange facility in Taiwan struck fear into those who knew its true purpose. S7 Ep8

Inside Man: A Middle Eastern region littered with ruins was the site of an extraordinary deception, and a strange facility in Taiwan struck fear into those who knew its true purpose. S7 Ep8

Shadow Factory: Eerie ruins hide in the forested hills of Arkansas, plus a disintegrating gulag in Albania that housed enemies of the state.