Given what you know about the state of affairs in Europe in 1914 as well as the main drivers that ultimately caused the fighting to break out in Europe, why do you think that the leaders of
Britain, France, Germany and Russia were not able to prevent the outbreak of war? Why didn't
diplomacy work?

As there had been tension between the countries for years as everyone wanted more land, more power and the strongest military and economic power. Also  as they all had signed a load of treaties out of fear of invasion or war. So when a bunch of young Serbians assassinated the heir to the Austro-Hungarian throne, The Austrian government thought that the Serbian leaders had ordered the murder [they most likely did] and declared war on Serbia, as Austria- Hungary had an alliance with Germany they declared war on Serbia but Serbia had an alliance with France, who had an alliance with Britain so both of them declared war on Austria and Germany.    

Explanation:

Fun Fact: the King of Britain, Emperor of Germany and Tsar of Russia were all first cousins and were all in power when they went to war.

saint genesius of rome was an actor, a comedian. according to the legend, he decided to fake his baptism, as in a play, before emperor diocletian. it is said that in the middle of his "baptism" -by a fake priest-, a miracle occurred when water came in contact with him, he really turned into a christian, a real one, and because of this he was tortured and executed. his own relics are allegedly held in the church of several churches in rome, namely: san giovanni della pigna, santa susanna di termini, and st. lawrence.