1917 was a pivotal year for both sides in the conduct of the First World War. Decisions made during that year were to have a profound impact on what happened the following year and the eventual outcome of the war. '1917' was a huge blockbuster success and was inspired by the director's great-grandfather. So how much was fiction and how much was fact? This documentary analyses the movie and looks at what elements are true, the real-life characters and what became of them.