WW1

World War I (WWI or WW1), also called the First World War, began on July 28, 1914 and lasted until November 11, 1918. It was a global war and lasted exactly 4 years, 3 months and 2 weeks. Most of the fighting was in continental Europe.

Soldiers from many countries took part, and it changed the colonial empires of the European powers. Before World War II began in 1939, World War I was called the Great War, or the World War. Other names are the Imperialist War and the Four years War. There were 135 countries that took part in World War I, and nearly 10 million people died while fighting.[7]

Before the war, European countries had formed alliances to protect themselves. However, that made them divide themselves into two groups. When Archduke Franz Ferdinand of Austria was assassinated on June 28, 1914, Austria-Hungary blamed Serbia and declared war on it. Russia then declared war on Austria-Hungary, which set off a chain of events in which members from both groups of countries declared war on each other.

The two sides were the Allied Powers (mainly Russia, France, the British Empire and later the United States) and the Central Powers (mainly Germany, Austria-Hungary and the Ottoman Empire).

There was fighting in many different fronts (areas). The French and the British fought the Germans on the Western Front in France and Belgium. Germany had tried to defeat France quickly with the Schlieffen Plan but were stopped in the First Battle of the Marne. Most of the fighting on the western front was trench warfare. The Russians fought the Germans and Austro-Hungarians on the Eastern Front in Central and Eastern Europe. Fighting on the eastern front was not trench warfare as in the west, but mobile warfare. The other main areas of fighting were in the Middle East, in the Gallipoli region of the Ottoman Empire and between Italy and Austria-Hungary. Fighting also took place in Africa, China, at sea and in the air. World War I was the first major war in which tanks, airplanes and submarines (or U-boats) were important weapons.

In 1917, the Russian Revolution led to Russia leaving the war in March 1918. Also in 1917, the United States entered the war, but it took a year for most of its army to arrive. From the time of the Russian departure, before the American arrival, the Germans launched a huge attack in March 1918 to try to win the war, but it failed.

From August to November 1918, the Allied Powers won a large victory against the Germans during the Hundred Days Offensive. Austria-Hungary and the Ottoman Empire then agreed to stop fighting. The German government collapsed, and a new government was forced to agree to stop the fighting on November 11, 1918. Basically, the Germans ran out of men.

Also, the influenza pandemic of 1918 had a big influence. It killed many people in Europe: it lasted for three years, from January 1918 to December 1920.[8] About 500 million[8] people were infected across the world which then had a population of 1.80 billion people.

The war was ended by the signing of many different treaties, the most important being the Treaty of Versailles. It also led to the creation of the League of Nations, which was meant to prevent wars. People were shocked by the size of the war, how many people it killed and how much damage it caused. They hoped it would be "the war to end all wars". Instead, it led to another, larger, world war 21 years later.