Look at this picture. It shows one of the many cemeteries after the siege of Sarajevo. Seeing how the cemeteries have replaced parks and sports facilities in the urban landscape is a testament to the suffering of Sarajevo.
But we humans don't change. We may think we are civilized and that law and order rules. We are so wrong!
The idea that a group of people can claim land where others live still lives on. The German ideas of lebensraum and übermensch have been inherited by disgusting regimes in Asia Minor, the Holy Land, former Yugoslavia, and so on. A common factor seems to be that some old story justifies sionists', serbs and others claim to land that is inhabited by others.
If they were in their right, then native americans could claim the Americas, the sami people could claim Scandinavia, and Scandinavians could claim the Hunnic empire. But that wouldn't make the world a better place, would it. So why does the international community allow this mentality to live on?