The Iraq War began in March 2003 with an invasion of Iraq by a U.S.-led 'coalition of the willing.'

The stated rationale for the invasion by the administration of President George W. Bush was that Iraq possessed weapons of mass destruction (WMDs).

Additional justifications included alleged links between Saddam Hussein's regime and Al-Qaeda, and the goal of liberating the Iraqi people.

The invasion was highly controversial and did not have the explicit authorization of the UN Security Council.

The initial military campaign was swift, overthrowing Saddam Hussein's government in a matter of weeks.

However, no stockpiles of WMDs were ever found in Iraq, undermining the primary justification for the war.

The post-invasion period was marked by a long and violent insurgency against U.S. and coalition forces.

The conflict also ignited a brutal sectarian civil war between Iraq's Sunni and Shia Muslim communities.

The 'surge' of U.S. troops in 2007 helped to temporarily reduce the levels of violence.

The war had profound long-term consequences, including the destabilization of the region and contributing to the rise of the Islamic State (ISIS).