When a handful of British volunteers were pitted against the might of the German battleship Tirpitz in 1943, official records described the raid as the most daring attack of the Second World War. Four-man X-class midget submarines battled for 11 days across arctic seas to the impregnable Norwegian fjord where Germany's biggest ship awaited them. While crew members from two of the vessels survived, mystery has always surrounded the role of the X5's crew. Now a team of divers seeks out the truth in order to reveal the story of the unsung heroes. 2/6.

Could a set of hieroglyphs be about to change the face of Ancient Egypt for ever? Doctor Viv Davies claims that this recent discovery proves that in 800 BC, Egypt was under the rule of 'black Pharaohs' from neighbouring Nubia. As the British Museum prepares an international exhibition of additional finds that seem to corroborate his assertion, this programme accompanies Doctor Davies on his final digs to unearth more clues to the lives of these long-forgotten rulers. 4/6.

When Stalin's death from a brain hemorrhage was announced in March 1953, the true details surrounding his death were immediately suppressed: the Soviet Communist Party's power would crumble if foul play was suspected. Acclaimed historian Simon Sebag-Montefiore plays detective, travelling to Moscow to investigate. For the first time, the content of secret KGB files is examined and the official version of Stalin's death is denounced as lies, while interviews with witnesses and experts present an array of motives and suspects. 2/5.