"Why war broke out in Europe" They're many reasons why world war one stared. World war one was caused by alliances, nationalism, and the assassination of the Archduke of Austria-Hungary. These reasons are just some reasons of why ww1 was caused.
The alliances were a cause of ww1. Austria-Hungary was allied with Germany and Italy. Serbia was allied with Bosnia, France, Russia, and Great Britain (who is allied with America). These alliances made the countries ready for war. The alliances caused the war because when Austria-Hungary and Serbia went to war Germany, Bosnia, Russia, France, and Great Britain (America in 1917) all went to war as well. The alliances were a big reason for bringing all the country in to a "world war".
Nationalism "" Patriotic feeling for ones own nation, a desire or movement for independence as a nation. Nationalism was a cause of ww1. The European countries at this time were very rival towards each other for land and military power.
Austria-Hungary wanted control over the Balkans but Serbia didn't want that so they stared to fight. Great Britain had a very large and very powerful navy Germany wanted to match it. Russia, France and Germany all tried to beat each other in having the larger army. All these counties fighting and competing contributed to the start of ww1.
On June 28, 1914 the Archduke Francis Ferdinand and his wife Sophie were assassinated. A young Serbian named Gavrilo Princip shot the Archduke and his wife on the crowded streets of Sarajevo (Yugoslavia). By killing the archduke who was heir to the thorn of Austria-Hungary when the ruler of Austria-Hungary dies they wont have any one to take control of the nation crating chaos in the long run. The young Serbian showed strong nationalism but by...