Apart from the beginning and end, did World War I consist entirely of trench Warfare?

No. Trench warfare was only the norm on the Western Front, as well as the fairly short line between Italy and Austria-Hungary (most of their borders being mountainous and impassible to large formations). This was due to the large concentration of soldiers packed into a relatively small space. (A front of 475 miles, bordered on one side by the ocean, and on the other by the armed neutral Switzerland, with each side having a density of roughly 1 man per foot.) On the Eastern Front., there were not enough soldiers to hold a solid line in force. The war there was more characterized by scattered outposts, flanking maneuvers, and large advances and retreats, and even by the use of cavalry, which proved all but worthless in the west. We hear more about the Western front for several reasons. For one thing, it is where all British, French, Italian, and American forces fought, as well as the majority of German forces. Furthermore, it is where the first offensive of the war took place, where ...  more