Can someone point me the Sutra that explains the fall of Human civilization?

There is a sutra about the downfall of our civilization. It explains how some people flee the urban life and live in far away places while others go into a Killing spree/ War. It also features how the people who fled come to their senses and how they build a proper society again. This is a Sutra in Sutra pitaka (Theravada). Can someone name this and give me a link?