Dan Snow introduces a selection of 'Voices of the First World War' programmes covering the developments of 1915. In archive interviews from the BBC and Imperial War Museum, those who witnessed it recall the battle of Neuve Chappelle, the first major use of gas on the Western Front and the effect on the soldiers who breathed it in, and what it was like to be in command of U-boats - or be at their mercy: we hear from a survivor of the sinking of the Lusitania. And those who fought in Gallipoli recall the landings, the terrible conditions they suffered on the peninsula, and their eventual evacuation. Show less