Iraq War: Baghdad falls to American forces; Iraqis turn on symbols of their former leader Saddam Hussein, pulling down a grand statue of him and tearing it to pieces.

Baghdad (; Arabic: [badad] (listen)) is the capital of Iraq and the second-largest city in the Arab world after Cairo. It is located on the Tigris near the ruins of the ancient Akkadian city of Babylon and the Sassanid Persian capital of Ctesiphon. In 762 CE, Baghdad was chosen as the capital of the Abbasid Caliphate, and became its most notable major development project. Within a short time, the city evolved into a significant cultural, commercial, and intellectual center of the Muslim world. This, in addition to housing several key academic institutions, including the House of Wisdom, as well as a multiethnic and multi-religious environment, garnered it a worldwide reputation as the "Center of Learning".

Baghdad was the largest city in the world for much of the Abbasid era during the Islamic Golden Age, peaking at a population of more than a million. The city was largely destroyed at the hands of the Mongol Empire in 1258, resulting in a decline that would linger through many centuries due to frequent plagues and multiple successive empires. With the recognition of Iraq as an independent state (formerly the British Mandate of Mesopotamia) in 1932, Baghdad gradually regained some of its former prominence as a significant center of Arab culture, with a population variously estimated at 6 or over 7 million. Compared to its large population, it has a small area at just 673 square kilometers (260 sq mi).

The city has faced severe infrastructural damage due to the Iraq War, which began with the United States-led invasion of Iraq in 2003 and lasted until 2011, and the subsequent insurgency and renewed war that lasted until 2017, resulting in a substantial loss of cultural heritage and historical artifacts. During this period, Baghdad had one of the highest rates of terrorist attacks in the world. However, terrorist attacks are rare and have been declining since the territorial defeat of the Islamic State militant group in Iraq in 2017.

The Iraq War was a protracted armed conflict in Iraq from 2003 to 2011 that began with the invasion of Iraq by the United States–led coalition which overthrew the Iraqi government of Saddam Hussein. The conflict continued for much of the next decade as an insurgency emerged to oppose the coalition forces and the post-invasion Iraqi government. US troops were officially withdrawn in 2011. The United States became re-involved in 2014 at the head of a new coalition, and the insurgency and many dimensions of the armed conflict continue today. The invasion occurred as part of the George W. Bush administration's War on Terror following the September 11 attacks, despite there being no connection between the attacks and Iraq.In October 2002, Congress granted President Bush the power to decide whether to launch any military attack in Iraq. The Iraq War began on 20 March 2003, when the US, joined by the UK, Australia, and Poland, launched a "shock and awe" bombing campaign. Iraqi forces were quickly overwhelmed as coalition forces swept through the country. The invasion led to the collapse of the Ba'athist government; Saddam Hussein was captured during Operation Red Dawn in December of that same year and executed three years later. The power vacuum following Saddam's demise and mismanagement by the Coalition Provisional Authority led to widespread civil war between Shias and Sunnis, as well as a lengthy insurgency against coalition forces. Many of the violent insurgent groups were supported by Iran or al-Qaeda in Iraq, with Iran giving support for predominantly Shia militias battling Al-Qaeda and other Sunni groups. The United States responded with a build-up of 170,000 troops in 2007. This build-up gave greater control to Iraq's government and military, and was judged a success by many. In 2008, President Bush agreed to a withdrawal of all US combat troops from Iraq. The withdrawal was completed under President Barack Obama in December 2011.The United States based its rationale for the invasion on claims that Iraq had a weapons of mass destruction (WMD) program and posed a threat to the United States and its allies. Additionally, some US officials falsely accused Saddam of harbouring and supporting al-Qaeda. In 2004, the 9/11 Commission concluded there was no evidence of any relationship between Saddam's regime and al-Qaeda. No stockpiles of WMDs or active WMD program were ever found in Iraq. Bush administration officials made numerous claims about a purported Saddam–al-Qaeda relationship and WMDs that were based on sketchy evidence rejected by intelligence officials. The rationale for war faced heavy criticism both domestically and internationally. Kofi Annan, then the Secretary-General of the United Nations, called the invasion illegal under international law, as it violated the UN Charter. The 2016 Chilcot Report, a British inquiry into the United Kingdom's decision to go to war, concluded that not every peaceful alternative had been examined, that the UK and US had undermined the United Nations Security Council in the process of declaring war, that the process of identification for a legal basis of war was "far from satisfactory", and that, taken together, the war was unnecessary. When interrogated by the FBI, Saddam Hussein confirmed that Iraq did not have weapons of mass destruction prior to the US invasion.In the aftermath of the invasion, Iraq held multi-party elections in 2005. Nouri al-Maliki became Prime Minister in 2006 and remained in office until 2014. The al-Maliki government enacted policies that alienated the country's previously dominant Sunni minority and worsened sectarian tensions. In the summer of 2014, ISIL launched a military offensive in northern Iraq and declared a worldwide Islamic caliphate, leading to Operation Inherent Resolve, another military response from the United States and its allies. According to a 2019 US Army study, Iran has emerged as "the only victor" of the war.An estimated 151,000 to 1,033,000 Iraqis died in the first three to five years of conflict. In total,

the war caused at least one hundred thousand civilian deaths, as well as tens of thousands of military deaths (see estimates below). The majority of deaths occurred as a result of the insurgency and civil conflicts between 2004 and 2007. Subsequently, the War in Iraq of 2013 to 2017, which is considered a domino effect of the invasion and occupation, caused at least 155,000 deaths, in addition to the displacement of more than 3.3 million people within the country.