The 2003 US-led invasion of Iraq was meant to topple a dictator who had inflicted reckless wars and economic misery on his fellow Iraqis, and then to usher in a thriving democracy.
Instead, Iraqis faced years of upheaval and chaos.
A devastating insurgency, first by Saddam Hussein loyalists and then by Al Qaeda, was followed by a sectarian civil war and, later, the rise of Daesh, which occupied a third of the country and slaughtered thousands.
Here is a look at some of the violence, including suicide bombings and beheadings that has plagued Iraq, a major OPEC oil producer and key US ally, since the 2003 war.
20 March 2003
US-led forces invade Iraq from Kuwait to oust Saddam Hussein. The attack crushes the Iraqi military and chases Saddam from power in a span of weeks.
READ: Two decades after Saddams fall, Iraqis still haunted by disappearances
9 April, 2003
US troops seize Baghdad. Saddam goes into hiding. Lawlessness emerges in Baghdad and elsewhere.
1 May 1, 2003
President George W. Bush declares that "the United States and our allies have prevailed" in Iraq. As he spoke aboard the aircraft carrier, Abraham Lincoln, a banner behind him stated, "Mission Accomplished".
23 May, 2003
Coalition Provisional Authority Head, Paul Bremer, disbands Iraq's army and intelligence services, sending hundreds of thousands of angry armed men into the streets.
7 August, 2003
At least 17 people are killed in a truck bomb attack on Jordan's Embassy in Baghdad.
19 August, 2003
Suicide truck bomb wrecks UN headquarters in Baghdad, killing 22 people including UN Envoy, Sergio Vieira de Mello.
29 August, 2003
A car bomb kills at least 83 people, including top Shia Muslim leader, Ayatollah Mohammed Baqer Al-Hakim, at Imam Ali mosque in Najaf.
Insurgency against US-led forces emerges, waged by pro-Saddam guerrillas, then Al Qaeda and Shia fighters. US Forces fail to find weapons of mass destruction.
READ: US CENTCOM Commander Erik Kurilla pays visit to north-eastern Syria
13 December, 2003
U.S. troops capture Saddam, bearded and bedraggled, hiding in an underground bunker near Tikrit.
Insurgency intensifies in Falluja and elsewhere in mainly Sunni Muslim Anbar province, and violence by followers of Shia cleric, Moqtada Sadr, in the south. US faces international condemnation after photographs emerge showing abuse of detainees at Abu Ghraib jail.
31 March, 2004
In Fallujah, four Blackwater private security contractors are killed and some of the burnt bodies hung from a bridge.
11 May, 2004
Kidnappers behead US businessman, Nicholas Berg, and videotape his killing.
Al Qaeda leader in Iraq, Abu Musab Al-Zarqawi, starts waging bloody attacks designed to turn majority Shia Muslims against minority Sunnis in a civil war.
READ: US investors warn Israel judicial overhaul will prevent future investments
8 June, 2006
Zarqawi is killed by US Forces.
30 December, 2006
Saddam Hussein hanged by masked executioners after Iraqi court sentences him to death for killings of 148 men and boys in northern Iraq in 1982.
Bush announces a new war strategy including a "surge" of US troops into Iraq to combat the insurgency.
Iraq says security guards from the US firm, Blackwater "deliberately killed" 17 Iraqis in a shooting in Baghdad, and plans legal steps against them. Blackwater says its guards reacted lawfully to an attack on a convoy.
Last US combat brigade leaves Iraq.
4 July, 2014
Daesh leader, Abu Bakr Al-Baghdadi, seizes world's attention by climbing the pulpit of Mosul's medieval Al-Nuri mosque in black clerical garb on a Friday to declare his caliphate.
Daesh's brutal rule, during which it killed and executed thousands in the name of a narrow interpretation of Islam, comes to an end in Mosul when Iraqi and international forces defeat the group there.
19 October, 2018
President Donald Trump declares Daesh defeated.
27 October, 2019
Trump announces Daesh leader, Abu Bakr Al-Baghdadi, killed himself during a night raid by US Special Forces in Syria. Baghdadi dies alongside three of his children by detonating an explosives-laden vest when he fled into a dead-end tunnel during the attack.
READ: Saudi Arabia refuses visas for Israeli delegation to UN tourism event