Time magazine has a very interesting article and photo gallery about the Balkan Wars of 1912-13. Here's their introduction.
A century ago today, the Balkan wars began. On Oct. 8, 1912, the tiny Kingdom of Montenegro declared war on the weak Ottoman Empire, launching an invasion of Albania, then under nominal Turkish rule. Three other Balkan states in league with the Montenegrins — Bulgaria, Greece and Serbia — rapidly followed suit, waging war on the old imperial enemy while drawing upon a wellspring of national sentiment in each of their homelands. By March 1913, their blood-soaked campaigns had effectively pushed the enfeebled Ottomans out of Europe. Yet by July, Greece and Serbia would clash with Bulgaria in what’s known as the Second Balkan War — a bitter monthlong struggle that saw more territory change hands, more villages razed and more bodies dumped into the earth.
The peace that followed was no peace at all. A year later, with Europe’s great powers entwined in the fate of the Balkans, a Yugoslav nationalist in the Bosnian city of Sarajevo killed the crown prince of the Austro-Hungarian Empire. Europe plunged into World War I.
There's much more at the link. Very interesting reading, particularly in the light of the 1990's Balkan wars, the present situation in Greece and the current uprising in Syria.
Could such wars break out again? You bet your life they could! If the European economy goes to hell in a handbasket, similar conflicts may become more probable than possible. In times of dire distress, people always seek to blame something or someone else for their plight, and take out their anger, frustration and fear on them. Their political leaders are usually only too happy to oblige, as this turns public attention away from their mishandling of events and re-focuses it on alleged internal 'traitors' and/or external 'enemies'. Since history teaches us that human beings haven't learned from their mistakes over several millennia of shared existence, why should things be different now?