World War I

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World War 1. Explain like I'm 5.

Who, what, when, where and most importantly, why?
 * Question
 * Answer by /u/Axon350

Best answer
1914: The Archduke Franz Ferdinand of Austria-Hungary goes to the nearby country of Serbia to check out what's going on. Everybody's cool, then BAM! Serbian nationalist Gavrilo Princip pops a cap in his ass. Austria-Hungary doesn't like this very much, as you can imagine. Germany advises Austria-Hungary to order Serbia to pay damages. After a while, Austria-Hungary comes up with a ridiculously complicated list of things for Serbia's punishment. Serbia refuses, and Austria-Hungary declares war.

Germany joins up with Austria-Hungary, Russia backs up Serbia, and the war begins on the Eastern Front. Germany planned to attack Russia, but had to go through Belgium to do it. This angered France (because it was allied with Belgium) and Great Britain, and soon Britain had declared war on Germany. Another reason that Britain joined was that Britain had a number of colonies in faraway countries generating revenue, and was worried that if Germany beat France, they'd lose their colonies.

Turkey, Greece, Italy, and Romania also joined the party because of similar reasons: They felt that they had to protect their allies, that they might lose territory, or they just didn't like the other guys and needed an excuse to fight. Meanwhile, the USA was remaining neutral. "This is Europe's war!" they harrumphed, then went back to smoking indoors and denying women the vote. However, they sneakily supplied Great Britain with food and supplies. The Germans found out about this, and attacked the supply ship Lusitania. At the same time, they tried to bribe Mexico into fighting against the US. The British intercepted the bribe and notified the US, and it was the final straw. In 1917, the United States entered World War 1.

The Germans knew they were pretty beat, but made a final push at the Allies' weakest point before the Americans got there. They got some ground against the Allies, but then the Americans arrived and wiped the floor with the Central Powers. Which is good, because Russia was out of the game because the Russian citizens took an opportunity in 1917 to overthrow the government. Germany surrendered in 1918, at 11:00 on November 11. They signed the Treaty of Versailles, but it was so harsh and they had to pay so much in reparations that Germany would eventually start the Second World War. But that's another story.

Source.