In the quest for world domination, the Nazis built some of the biggest and deadliest pieces of military hardware and malevolent technology in history. Creating huge terror machines, hi-tech superguns and some of the original weapons of mass destruction, their aim was to control a nation, conquer a continent and win the war. Over six episodes, the series uncovers the hidden remains of Hitler's most ambitious megastructures, telling the stories of the engineers who designed them and revealing how these structures sparked a technological revolution that changed warfare forever. In the first programme, discover the story behind the defensive wall, stretching thousands of kilometres, built by the Third Reich to protect themselves from the Allies.