World War I is probably one of the biggest war that contained so much “chain reaction”. One feels threatened, they ally with their friends, and another nation feels threatened, so they ally with their friends. The feeling of threat leads into invasions then leads into their allies helping and invading and pretty soon, more allies come from both sides. Sooner or later, a vast amount of area, in this case a whole continent, is on a war. Silly as it may sound, this was World War I. We only hope that the “feelings of threat” was the c ....