Quick Answer: The International Court of Justice, or colloquially the World Court, is the principal judicial organ of the United Nations. It settles legal disputes submitted to it by states and provides advisory opinions on legal questions referred to it by other UN organs and specialized agencies. The ICJ is the only international court that adjudicates general disputes between countries, with its rulings and opinions serving as primary sources of international law. It is one of the six principal organs of the United Nations. Established in June 1945 by the Charter of the United Nations, the court began work in April 1946. It is the successor to the Permanent Court of International Justice, which was established by the League of Nations in 1920. Its founding statute is an integral part of the UN Charter and draws heavily from that of its predecessor. All UN member states are automatically parties to the ICJ Statute.