This five-part series was produced using over 500 hours of archival footage unearthed after exhaustive research in archives, film libraries and private collections around the world. Much of the footage is previously unseen. It has been meticulously restored and colourized to create a powerful, evocative look at this tragic period in world history. How did such a cruel and far-reaching conflict occur? How did men and women endure the atrocity for four long years? The series takes us to the battlefields, inside the minds of those who governed, and to the heart of life behind the frontlines. Civilians and soldiers, anonymous or well-known - the series bears witness to their unimaginable suffering and their struggle to survive in this time of uninhibited violence: as heroic as it was barbaric.