20,000 years ago, the average person stood a 10-20% chance of dying violently. Today, the chance is under 1%. We have cut rates of violent death by 90% by creating large organisations that impose peace; but the main method for creating these organisations has been war. In effect, violence has slowly been putting itself out of business. The broad trends suggest that this process will probably continue. A talk by Prof. Ian Morris, Philippe Roman Chair in History and International Affairs at LSE IDEAS for 2015-16.