* World War 1 began on July 28, 1914 and lasted until November 11, 1918. Differences in foreign policies were to blame, although the immediate cause was the assassination of Austria’s Archduke Ferdinand. * The two main sides were the Allies, which included France, Great Britainand Russia; and Germany and Austria-Hungary. In total, 30 countries were involved in the conflict. Italy, once part of the Triple Alliance with Germany and Austria-Hungary, fought on the side of the Allies. * Soldiers fought largely in trenches during the war, and thousands suffered from stress, known as shell-shock. The British and French trenches were often squalid, whereas the German trenches were almost luxurious in comparison, with bunks and decent cooking facilities. (Click here to learn more about life in the trenches) * By the end of WW1, over 9 million soldiers had been killed, and another 21 million wounded. Over a million soldiers were killed in the infamous Battle of the Sommealone, including about 30,000 in just one day. * Around 11 percent of the population of France was killed or wounded during the war. About 116,000 Americans were killed, even though the US was only in the war for about 7 months.

* During World War 1, dogs were used to carry messages in capsules attached to their body. Dogs also carried and placed telegraph wires in important areas. * Pigeons were also used during the war. About 500,000 pigeons were regularly dropped into enemy lines by parachute, and then sent back with messages. * On Christmas Eve, 1914, both sides declared an unofficial truce and sung Christmascarols to each other. A football match was played in no-man’s land (the area between the German and British) trenches, and German and British soldiers exchanged food and souvenirs.The following Christmas, sentries on both sides had orders to shoot any soldier who did this.