The outbreak of the Second World War changed the world’s perspective on what constitutes a core value for society. The international community needed an effective instrument for cooperation, in order to preserve and defend human rights, international security, peace-making and peacekeeping. Thus, international public law emerged as an independent law branch, and consequently, international criminal law developed. The present paper attempts to analyse the latter from a historical and comparative law perspective, highlighting the key elements of international crime, what distinguishes it from a national one, and why does the international community need to support such an institution.