Islamabad (Urdu: اسلام آباد Islām ābād) is the capital of Pakistan and the ninth largest city in the country. Located within theIslamabad Capital Territory (ICT), the population of the city has grown from 100,000 in 1951 to 1.15 million as of 2011. The greaterIslamabad-Rawalpindi Metropolitan Area is the third largest conurbation in Pakistan with a population of over 4.5 million inhabitants.
Islamabad is located in the Pothohar Plateau in the northeastern part of the country, within the Islamabad Capital Territory.
The region has historically been a part of the crossroads of Punjab and Khyber Pakhtunkhwa with Margalla pass acting as the gateway between the two regions. The city was built during the 1960s to replace Karachi as Pakistan's capital. Islamabad is a well-organised international city divided into several different sectors and zones. It is regarded as the most developed city in Pakistan and is ranked as a Gamma- world city.The city is home to Faisal Mosque, the largest mosque in South Asia and the fourth 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, includingQuaid-i-Azam University, Pakistan Institute of Engineering & Applied Sciences and National University of Sciences and Technology. Allama Iqbal Open University in Islamabad is one of the world's largest universities by enrollment.