Wars are the biggest killers of humanity in the recent times. All wars are a loss to humanity, no matter who comes out victorious. Over the last century millions of lives have been lost in wars, the biggest being the World Wars I and II.
Wars are generally fought to establish the supremacy of a nation or of a people. Whatever be the reason, it is a very short sighted act, in which millions of precious innocent lives are lost and the dangerous effects are suffered even by future generations. With nuclear weapons the effects are disastrous.
It is in the interest of the arms industry to have some or the other conflict going on in the world which keeps their supply chain alive. Bigger and better weapons of mass destruction are being manufactured.
Wars can only be wiped out if there is enough awareness among the global population about the true benefactors of any war.