Looking out across a battlefield from an Anzac pill box near the Belgian city of Ypres in West Flanders in 1917. When German forces met stiff resistance in northern France in 1914, a "race to the sea" developed as France and Germany tried to outflank each other, establishing battle lines that stretched from Switzerland to the North Sea. Allies and Central Powers literally dug in, excavating thousands of miles of defensive trenches, and trying desperately to break through the other side for years, at unspeakably huge cost in blood and treasure.