Pakistan is located in Southern Asia bordering the Arabian Sea, between India to the east and Iran and Afghanistan to the west and China to the north. The majority of Pakistan's population lives along the Indus River valley and along an arc formed by the cities of Faisalabad,
Lahore, Rawalpindi/Islamabad, and Peshawar.
Archeological explorations have revealed impressive ruins of a 4,500-year old urban civilization in Pakistan's Indus River valley. The reason for the total collapse of this highly developed culture is unknown. A possible theory is that it was crushed by successive invasions (circa 2000 B.C. through 1400 B.C.) of Aryans and Indo-European warrior tribes from the Caucasus region in what is now Russia. The Aryans were followed in 500 B.C. by Persians and, in 326 B.C., by Alexander the Great. Archeological research on the area continues.
The Pakistan constitution of August 1973, amended substantially in 1985 under Muhammad Zia ul-Haq, provides for a President (Chief of State) elected for a 5-year term by an Electoral College that consists of the Senate, National Assembly, and the members of the four provincial assemblies; and a Prime Minister (head of government) elected by the National Assembly in a special session. After the election, the President invites the Prime Minister to create a government. The constitution permits a vote of "no confidence" against the Prime Minister by a majority of the entire National Assembly, provided that it is not in the annual budget session.
CIA World Factbook, U.S. State Department Background Notes, 11/1997