Question: why balkan is the powder keg of world war 1? 

Answer: I think you mean "the Balkans," not balkan.\n\nHere is a little background on the start of World War I:\n\nOn June 28, 1914, Archduke Francis Ferdinand of Austria-Hungary was assassinated. He was murdered at Sarajevo, the capital of the Austrian province of Bosnia. The assassin was Gavrilo Princip, a Serbian-trained Bosnian terrorist. Austria claimed that Serbian government officials had trained and equipped Princip's group, which was known as the Black Hand. For many years Serbia and Austria-Hungary had been unfriendly because Serbian nationalists wanted to unite all Slavic peoples living in the Balkan region into a single state. Slavs living in Austria-Hungary would be included, and Austria-Hungary strongly opposed this.\n\nSo, as you can see, the Balkan region is where the tensions of the Bosnians and Serbs ignited the war. They called upon their allies and World War I began.
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