Islamabad (Urdu: اسلام آباد; Islām ābād, lit. Abode of Islam) is the capital of Pakistan and the tenth largest city in the country. The population of the city has increased from 100,000 in 1951 to 1.21 million in 2009. The Rawalpindi/Islamabad Metropolitan Area is the third largest in Pakistan with a population of over 4.5 million inhabitants.
Islamabad is located in the Pothohar Plateau in the north of the country, within the Islamabad Capital Territory. The region has historically been a part of Punjab. The city was built during the 1960s to replace Karachi as Pakistan's capital.
Islamabad is a well-organized city divided into different sectors and zones. It was ranked as a Gamma world city in 2008. The city is home to the famous Faisal Mosque, the largest mosque in South Asia and the sixth largest mosque in the world.
Islamabad has the highest literacy rate in Pakistan and is home to the some of the top ranked universities in Pakistan, including Quaid-i-Azam University, Pakistan Institute of Engineering & Applied Sciences and the National University of Sciences and Technology. Allama Iqbal Open University in Islamabad is the world's largest university by enrollment.