Iraq war 20 years on: How invasion plunged country into decades of chaos

The invasion of March 2003 was a catastrophe for Iraq and its people.

More proof of that, measured in broken lives, was at a suspected site of a mass grave in the desert outside Sinjar, not far from the border with Syria.

Survivors of one of Iraq's damaged communities, the Yazidis, looked on as the earth in a marble quarry was excavated. On a wire fence around the site were photos of dozens of people, mostly men, who had been killed by jihadists from the Islamic State group. They were from Zile-li, a village near the quarry, where 1,800 men were taken and killed on 3 August 2014.

The Yazidis revere both the Quran and the Bible; their religion is influenced by both Christianity and Islam. Islamic State considered them to be infidels and carried out a genocidal assault. It happened after the Americans and British had ended their occupation, but a direct line links the massacre to the invasion, and the disastrous years that followed.