The numerous bunkers, palaces and hideouts around Europe built by dictators to secure their authoritarian rule. The episode examines the purpose of the Riese network of bunkers, which was Nazi Germany's largest mining and construction project. The bunkers were dug by Nazi prisoners in a remote region of Poland, beginning in 1943. The programme explores whether the bunkers were a headquarters for Hitler or if they were used to build atomic bombs.

Albanian communist revolutionary and politician Enver Hoxha, who led his nation from 1944 until his death in 1985. He authorised the construction of hundreds of thousands of bunkers throughout the country, allowing his citizens to wage guerilla warfare against the enemy he was sure would come.