From the end of the First Battle of Ypres, at the end of the Race to the Sea, until
the last few months of the summer of 1918, the Western Front consisted of a relatively
static line of trench systems which stretched from the coast of the North Sea southwards
to the Swiss border.
The principal adversaries on the Western Front, were Germany to the East against
France and the United Kingdom to the West, with sizable contingents taken from the
Allied empires, especially the British Dominions. The United States entered the war
on the side of the Entente Powers in 1917.