Crimes against humanity are certain acts which are committed as part of a widespread or systematic attack directed against any civilian population or an identifiable part of a population. The first prosecution for crimes against humanity took place at the Nuremberg Trials. Crimes against humanity have since been prosecuted by other international courts - such as the International Criminal Tribunal for the former Yugoslavia and the International Criminal Court, as well as in domestic prosecutions. The law of crimes against humanity has primarily developed through the evolution of customary international law. Unlike war crimes and genocide, crimes against humanity are not codified in an international convention, although there is currently an international effort to establish such a treaty, led by the Crimes Against Humanity Initiative.