Baghdad[note 1] is the capital and largest city of Iraq, located along the Tigris in the central part of the country. With a population exceeding 7 million, it ranks among the most populous cities in the Middle East and Arab World and forms 22% of the country's population. Spanning an area of approximately 673 square kilometres (260 sq mi), Baghdad is the capital of its governorate and serves as Iraq's political, economic, and cultural hub.

Founded in 762 AD by Al-Mansur, Baghdad was the capital of the Abbasid Caliphate and became its most notable development project. The city evolved into a cultural 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 multi-ethnic and multi-religious environment, garnered it a worldwide reputation as the "Center of Learning". For much of the Abbasid era, during the Islamic Golden Age, Baghdad was one of the largest cities in the world and rivaled Chang'an, as the population peaked at more than one million. It 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 such as the Ilkhanate, White Sheep Turkoman, Turco–Persian, Mamluk Dynasty and the Ottoman Empire.

The city was part of the Ottoman Empire's Baghdad Vilayet until World War I, when it was captured by British forces in 1917. Baghdad became capital of the former Mandate of Mesopotamia in 1921. With the recognition of Iraq as an independent monarchy in 1932, it gradually regained some of its former prominence as a significant center of Arab culture. During the era of oil boom in Iraq, the city experienced a period of prosperity and growth. It faced severe infrastructural damage due to the Iraq War, which began with the invasion of Iraq in 2003, resulting in a substantial loss of cultural heritage and historical artifacts. Impacted by the subsequent 2011–2013 insurgency and renewed war from 2013 to 2017, during this period, it had one of the highest rates of terrorist attacks in the world. However, it has gradually been on the decline since the territorial defeat of the Islamic State militant group in Iraq in 2017, and are now rare.

As capital of Iraq, Baghdad is location of the seat of government, national institutions and government ministries and serves as headquarters to numerous companies. It generates 40% of Iraq's GDP. A major center of Islamic history, the city is home to numerous historic mosques, as well as churches, mandis and synagogues, highlighting the city's historical diversity. Baghdad is home to Mustansiriya University, one of the oldest universities and Masjid al-Kādhimayn, that is visited every year by millions of Shi'ite pilgrims. The city is home to important cultural sites such as the National Museum of Iraq, the Iraqi National Library and the National Media Center. It is also known as the "City of Palaces", as it is home to well-known palaces.

Source: https://en.wikipedia.org/wiki/Baghdad