It's been said that, if 11th September 2001 was the day the world changed for America, then 20th March 2003 was the day America changed for the world.
Four leading voices of the BBC's coverage in the last five years (Jim Muir; Magdi Abdelhadi; Lyse Doucet and John Simpson) give their varying assessments of how the Iraq invasion and subsequent insurgency developed, charting the missed opportunities and faulty assessments by the Coalition, and the murderous exploitation of Iraq's post-war frailty by Saddam loyalists and foreign Islamists.
We also look at how the ripples begun in the Sunni triangle have since spread globally affecting the political and diplomatic balance worldwide.
In the second part of How Iraq's War Shaped Our World, the BBC's Arab Affairs editor, Magdi Abdelhadi, examines how the war has impacted on Arab states.
In the aftermath of the invasion, President Bush set out his "freedom agenda" - promising to promote democracy across the Middle East.
Five years on Magdi Abdelhadi travels to Egypt to find out what happened to this dream. He looks at how, as things went wrong in Iraq, the Bush administration was forced to change tack.
Many Arab citizens now believe democracy is a much more distant prospect than before the war. We also hear how the Iraq war has re-inforced the growing Islamisation of social and political life in the Arab world, and fostered divisions between Sunni and Shia.
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