Both sides dug in and a line of trenches soon ran from the Channel to the Swiss frontier. The First Battle of Ypres (20 October-22 November 1914) marked the end of open and mobile warfare on the Western Front. The destructive power of modern artillery and machine guns forced soldiers to seek cover on the battlefield and dig in for protection. Weapons played a big part in creating the difficult and unusual circumstances of trench warfare which the British Army encountered during the First World War (1914-18).
