In the late nineteenth and twentieth centuries, after thousands of years of violent international conflict, efforts to establish global norms for nations in connection with war, diplomacy, economic relations, and human rights accelerated. These efforts resulted in the founding of the United Nations (which develops, codifies, and enforces international law), the International Court of Justice (which settles legal disputes among nations and provides advisory opinions on legal questions), and the International Criminal Court (which investigates and tries individuals charged with the gravest crimes of concern to the international community).