The beginning of the battle at Somme.
This battle originated because the French needed the Germans away from their Capital, Paris. The French and British Attacked the Germans up North. Making Germany remove some of their men to help out.
Unfortunately this didn't go to plan with France and Britain. The French losing 200 000 men, the British losing 420 000, counting the 60 000 lost on the first day.
This battle is the main source of Horror and leads us on how horrible the wars were.