Because it brought about profound changes to the world more so than any other event of the twentieth century. To list all the changes that it brought about would take a great deal of time and effort and is to large to answer here. Some of the major ones are. It launched America as a world power. It created the idea of the rights of nations. It helped bring about WW2 in Europe.it dissolved the Austro-Hungarian Empire. It reorder the Middle East. Created the country of Iraq. It brought about massive leaps in technological warfare. The are just a few.
