March 21, 2003: U.S. Marines with India Company, 3rd Battalion, 7th Marines, 1st Marine Division watch the perimeter in Az Bayer, Iraq.
Feb. 6: Secretary of State Colin Powell speaks to the U.N. Security Council to present evidence that Iraq was hiding weapons of mass destruction and that Saddam Hussein was deceiving U.N. weapons inspectors. Here he holds up a vial he says could contain anthrax.
Jan. 18: Tens of thousands of antiwar protesters gather on the National Mall in Washington to protest the possibility of a war in Iraq.
March 19: President Bush addresses the nation from the White House's Oval Office to announce the beginning of military action in Iraq.
March 20: After demanding that Saddam Hussein and his sons Uday and Qusay surrender and leave Iraq the U.S.-led coalition begins bombing Baghdad. The campaign, dubbed "Shock and Awe," uses massive bombs to destroyed many of Baghdad's government buildings.
March 21: Iraqi soldiers surrender in northern Kuwait as U.S. forces advance into Iraq and move toward Baghdad.
March 21: An anti-war protester, hand covered with a red substance, flashes a peace sign while being arrested during a demonstration outside the White House. Anti-war activists launched a campaign against the war that included sit-ins, mass rallies and quiet vigils. Hundreds were arrested.
March 22: U.S. Army soldiers take aim to provide security while convoy stops for refueling in southern Iraq in the early days of the war.
March 29: Soldiers of the British Light Infantry distribute aid packages to locals at Zubayr near Basra, southern Iraq. Britain, a key ally in the U.S.-coalition, was in charge of security in Iraq's southern region until its withdrawal in 2007.
April 9: U.S. Marines pull down a statue of Saddam Hussein in Baghdad's Firdos Square.
April 11: Two Iraqi women carry furniture away from an Iraqi government office building on fire downtown Baghdad. Widespread looting continued in the Iraqi capital.
May 1: President Bush declares the end of major combat operations in Iraq aboard aircraft carrier USS Abraham Lincoln. The war appeared at the time to be a success, but later, as conditions in Iraq deteriorated, the message of "mission accomplished" was criticized as premature.
Dec. 13: U.S. forces capture Saddam Hussein near his home town of Tikrit without firing a single shot. He had been hiding in the cellar of a farmhouse. "He was caught like a rat," Maj. Gen. Ray Odierno says.
March 31: Iraqis chant anti-American slogans as charred bodies of four military contractors hang from a bridge over the Euphrates River in Fallujah, west of Baghdad. The incident became a turning point in the war and illustrated the need to deal with the threat from the growing insurgency.
April 8: The first Battle for Fallujah was an offensive to capture or kill insurgent elements considered responsible for the deaths of the military contractors that were strung up on the city's bridge. Here U.S. Marines pray over a fallen comrade at a first aid point after he died from wounds suffered in the fighting.
The Pentagon was hit by a scandal in spring 2004, when photos taken at Abu Ghraib prison in Baghdad, Iraq, were leaked to the media, seeming to show mistreatment of Iraqis in U.S. custody. In this picture, an unidentified detainee stands on a box with a bag on his head and wires attached to him in late 2003.
June 28: U.S. Ambassador L. Paul Bremer and Iraqi President Sheikh Ghazi Ajil al-Yawar shake hands while others look on during a ceremony celebrating the transfer of full governmental authority to the Iraqi Interim Government from the U.S.-led Coalition Provisional Authority.
Dec. 10: An Abrams tank fires into a building during the second Battle for Fallujah. The Marines launched a another offensive --just months after the first -- in an aim to finally rid the city of its Al Qaeda-led insurgency that had taken hold of the city. The battle lasted about two weeks and left more than 50 Americans dead, but it paved the way for greater security in Iraq's western Al Anbar province.
Jan. 30: An Iraqi woman holds up her hand to show a purple finger, indicating she has just voted, as she leaves a polling station in the center of Az Zubayr, southern Iraq. In one of the most significant early developments in the war, Iraqis across the country turn out to vote in their country's first free election in a half-century, defying insurgents who launch deadly suicide bombings and mortar strikes at polling stations.
June 16: Even as Iraq's military began taking a greater role it the country's security, the U.S. Marines, like Lima Company, 3rd Battalion, 3rd Marine Regiment, still carried out house searched looking for insurgents.
Jan. 10: President Bush, speaking from the White House library, announces a new strategy in Iraq, quickly dubbed the "surge." The surge, which included the deployment of an additional 20,000 U.S. troops, was a seen as a key factor in helping to reduce violence.
Aug. 14: A member of the Sons of Iraq adjusts his ammunition belt in west Baghdad's Amariyah neighborhood in Iraq. Also known as the Sunni awakening movements, tribal leaders in Iraq's western Sunni Triangle, encouraged their members to join forces with the hated Iraqi police and U.S. forces to defeat the Al Qaeda-led insurgency. After the awakening, the Sunni Triangle became one of Iraq's safer areas.
Sept. 25: An Iraqi traffic policeman inspects a car destroyed by a Blackwater security detail in al-Nisoor Square in Baghdad, Iraq. Blackwater USA, later renamed Blackwater Worldwide and later Xe Services LLC, played a significant role during the Iraq War as a private security contractor. In 2003, the company received its first major contract, a $21 million no-bid deal to guard L. Paul Bremer, the head of the Coalition Provisional Authority. Blackwater/Xe would later come under fire for shipping hundreds of automatic firearms to Iraq without necessary permits and without paying the proper tariffs.
June 22: Members of a U.S.-backed Iraqi neighborhood patrol talk to U.S. soldiers at their checkpoint in a street in Baghdad's Sadr City. The rag-tag band of men is part of a plan to strengthen the Iraqi Army's hold over a bastion of anti-American Shiite cleric Moqtada al-Sadr.
Oct. 1: An Awakening Council member stands guard at a checkpoint in the district of Dora in Baghdad, Iraq. The Iraqi government took command of thousands of these Sunni fighters who helped quell violence by turning against Al Qaeda.
Nov. 10: A detainee performs his daily prayers at the U.S. detention facility at Camp Cropper in Baghdad, Iraq.
Dec. 14: A man throws a shoe at President Bush during a news conference with Iraq Prime Minister Nouri al-Maliki in Baghdad.
April 7: Just months after taking office, the Commander-in-Chief meets with with his top general in Iraq, Gen. Raymond T. Odierno. During Obama's visit with U.S. troops at Camp Victory, Baghdad. Obama 's visit comes after his announcement in February of an August 2010 deadline for withdrawing combat troops.
April 7: President Barack Obama addresses his remarks to hundreds of U.S. troops during his visit at Camp Victory, Iraq.
Sept. 9: U.S. Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff greets the children of service members killed during the wars in Afghanistan and Iraq at the Fourth Annual Time of Remembrance ceremony honoring America's fallen heroes.
Sept. 17: Vice President Joe Biden eats lunch with troops at the Pegasus dining facility in Camp Liberty, Iraq.
In an undated photo, the sun rises over the Camp Delta detention compound at Guantanamo Bay, which at one time held a peak population of 680 detainees. President Obama signed an order shortly after taking office to shut down the facility within a year on Jan. 22, 2009. As of July 2010, roughly 176 detainees remained at the prison camp.
July 18: Iraqi soldiers inspect the scene of a homicide attack in Radwaniya, southwest of Baghdad, Iraq. Twin homicide bombings killed scores of people, including dozens from a government-backed, anti-Al Qaeda militia lining up to collect their paychecks near a military base southwest of Baghdad, Iraqi officials said.
Aug. 13: Chuck Luther shows a tattoo on his forearm at his home near Fort Hood in Killeen, Texas. At the height of the Iraq war, the Army routinely fired hundreds of soldiers for having a personality disorder when they were more likely suffering from the traumatic stresses of war, discharge data suggests. Luther, who had served eight years in the Army, who been honorably discharged, and who rejoined after the Sept. 11 attacks, was one of them.
Aug. 19: U.S. Army Spc. Luisito Brooks gives a thumbs-up to the last Stryker armored vehicle of the 4th Brigade to leave Iraq, as it crosses the border into Kuwait at the Khabari border. A small number of combat troops remain in Iraq, likely to be transitioned into non-combat roles after Aug. 31, along with another 50,000 that will "advise and assist."
The mission known as Operation Iraqi Freedom began on March 20, 2003, and combat operations are officially scheduled to end Aug. 31, 2010. But the history of the war began much earlier and the United States' engagement in Iraq is expected to continue long after the last combat soldier leaves.