WW1 isn't a long war is around 4 year.It said that the begin reason is:
Erope and astria is the frist country to fight .,beacuse Europe has a king's son had died that someone as kill him.Europe think that it is astira's parson kill so, WorldWar1 begin.
The last many country went in this world war, like :china,Germany.......
(some of this imformation I find at other webside)
I went in this webside I saw a pitcure and I found some diffrent information by the frist webside.
that is :
When that time china isn't a big country,germany has china's part.Japen want that part too.Japen not really want to fight,but if they don't fight they won't get this part.germany want to give back that part to china, but they give to Japen.At may 4th this day, many people atv china begin to protest.
(some of this imformation I find at other webside)