The battle of the Somme (July 1-November 13, 1916) stands as one of the most horrific battles in history, with more than a million casualties. (Note: The figure given in the article seems to be an estimate of first-day British casualties, not of soldiers killed.)
From the Telegraph:
A British soldier's pocket diary of life in the trenches during the early days of the Battle of the Somme have been made public for the first time. Pte Walter Hutchinson was a young shop manager when he enlisted in the 10th Battalion, York and Lancaster Regiment. His poignant record of the battle, in 1916, includes a moving account of the first day during which more than 62,000 comrades died. Pte Hutchinson's handwritten account gives a graphic story of his own survival as wave after wave of soldiers went "over the top" only to be cut down by German fire.
The diary is being offered for sale at an auction in London tomorrow.
Forgotten diary captures horror of the Somme (telegraph.co.uk, via notebookism)Update:
Excerpts: Diary from the Somme (telegraph.co.uk)
Battle of the Somme (Wikipedia)
The diary of a First World War soldier who fought in the Battle of the Somme has been sold for £7,000.
Written by Walter Hutchinson, the diary went for almost ten times its original guide price at an auction in London.
Somme diary sold for £7k (UKTV)