The battle started at 07.30 on July 1, 1916 and petered out on November 18 as the onset of winter made further conflict impossible.
During those four and a half months over 30 million shells were fired. By the time the action came to a close, over 1,120,000 had been either killed or maimed in one of the fiercest conflicts in history.
To visualise what this means - consider it equates to sufficient names to fill four full-sized telephone directories.
