Tuesday is the 100th Anniversary of Jutland. Not Flanders fileds, but still the greatest surface fleet engagement ever fought.
German trenches at La Boiselle under British artillery bombardment on 1 July 1916. Comprising the main Allied attack on the Western Front during 1916, the Battle of the Somme is famous chiefly on account of the loss of 58,000 British troops (one third of them killed) on the first day of the battle, 1 July 1916,
http://firstworldwar.com/battles/somme.htm