what is the biggest things that happened under First World War and what is the biggest causes. I know that the biggest reason is the shooting of Franz Ferdinand of austria but is there anything else and is there any dates I should know

Explanation:

As the summer of 1914 approached, the balance of power in Europe looked shaky at best. It would take only a single crisis—the assassination of Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, and his wife Sophie Chotek by a young Bosnian Serb nationalist in Sarajevo—to push the continent’s six major powers into World War I, which devastated the continent and killed some 17 million soldiers and civilians.

But for all its historic importance, Franz Ferdinand and Sophie’s deaths might not have happened at all, if it weren’t for an odd series of events and decisions—and a wrong turn—that placed the royal couple squarely in the path of their assassin’s gun.

Why was Franz Ferdinand in Sarajevo?

In addition to being the heir to his uncle’s throne, Archduke Franz Ferdinand was also inspector general of the Austro-Hungarian Army, which had decided to hold its summer military exercises in Sarajevo, the Bosnian capital.

Back in 1908, the dual monarchy of Austria-Hungary had annexed Bosnia and Herzegovina, a region that had previously been under the control of the Ottoman Empire. Home to a largely Slavic population, Bosnia and Herzegovina had nationalist ambitions of their own, but nearby Serbia wanted to incorporate them into a pan-Slavic empire.

Wary of Serbia’s ambitions for territorial expansion, Austria-Hungary had sought and received assurances from Germany that it would stand behind the dual monarchy in case of war with Serbia (and Serbia’s powerful ally,

d. dr. francis collins