Dude, Hitler and Mussolini had nothing to do with the breakout of WWI, so just be careful.
I would point to the European system of Alliances breaking down. Bismarck, the master Prussian diplomat, had been out of action politically for nearly 20 years when WWI broke out. Basically, he devised many parts of the system, it's checks and balances, but without him to keep things stable, war was bound to break out.
Also think about Germany's growing strength as an industrial power to rival the British empire. Both had huge armies, and war as an outlet for trade tensions is a possible secondary explanation.
An interesting point to bring up is that there was hardly any land available to be given up as part of diplomatic negotiations. All the European territory was owned by one country or another, the land in Africa, China and the rest of Asia was pretty much carved up, and there was no land left to be traded in the Americas. So, in a sense, the only route left for countries who wanted to expand their power base, according to the imperialist political mindset at the time, was to invade other countries.
Franz Ferdinand's assassination is interesting, it's the microcosmic point of the war starting. If I remember correctly, he was the Grand Duke of Austria-Hungary, and he was killed by anarchists from the Balkan countries. Austria declared war on, was it Serbia? I forget... anyway, Russia said that they would support that country, Germany supported Austria, France supported Russia. I think Italy went with Germany, but I could be wrong there. Great Britain was virtually the last country to decide- if they'd pulled out, then it's possible that the war would have either not happened, or been a lot smaller scale if it did happen- but, GB decided to support France later on the negotiations, and that was that. Four years of carnage for Europe. You could argue that the strength of the British Empire was in decline by 1914, and they wanted to beat down their closest rival, Germany.
There had been an earlier incident- I think it was 1911, a German gunboat, the Leopard, sailed unnanounced into a Spanish harbour, and everyone thought that might start a war, though nothing came of it. The point is that the alliance system that had kept peace in Europe since 1870 was out of date, the business world was growing faster than anyone had seen it grow before, European empires were crying out for space to grow; with no master diplomat like Bismarck to renew it, war was an inevitability. Franz Ferdinand's assassination just happened to be the event over which everyone decided to fight. If he hadn't been killed, probably something else would have come along? Perhaps a socialist revolution in Russia would have done the trick?
Incidentally, Japan was a British ally at the time, and they had a great time, taking over former German colonies in Asia and otherwise producing lots of industrial goods whilst Europe was busy. They came out of WWI in a good position, though this was not reflected in the treaty of Versailles. In fact, I think the Japanese were still fighting the Russians well into 1925, I think it was in an effort to restore the Tsarist system- or possibly, just so that they could win extra territory, like that lovely island of Sakhalin above Hokkaido. Mmm, nice!
So, Britain and Germany had a war to see who was the strongest. Who won? The USA. Same goes for WWII.
I hope this stuff helps you out, but man, try to make it to those history lessons in future... unless you're sick, you should go.