Throughout World War I, Allied Forces led by the United Kingdom and the United States were stalled at trenches on the Western Front.

Western Front, a stationary line running through Europe north to south primarily over France, during several phases of World War I and World War II, dividing territories occupied by the United Kingdom, United States and allied forces to the west of the line versus German occupied territories to the east of the line.

A relative Eastern Front ran through Europe north to south, primarily over western Russia, dividing territories occupied by Germany to the west of the line versus Russian occupied territories to the east of the line. A relative Alpine Front was a line running east to west along the border of Austria-Hungary and Italy, dividing territories occupied by the United Kingdom, United States and allied forces to the south of the line versus German occupied territories to the north of the line.

World War I

The Western Front of World War I was defined in 1914 when allied forces were thrust into a stalemate against Germany along a frontline stretching from the North Sea southward through Switzerland. For years, both sides were stalled at these positions along the frontline and fought each other continuously from the same parallel trench networks. Each side tried to break through the Western Front but could not amass enough strength to do so until 1916 when the front began to move eastward.