Here's a look at what you need to know about Pakistan, the sixth most populous country in the world. It borders Iran, Afghanistan and India in Southeast Asia. In 1947, Pakistan gained its independence from Great Britain.
About Pakistan: (from the CIA World Factbook) Land Area: 796,095 sq km (slightly less than twice the size of California)
Population: 193,238,868 (2013 est.)
Median age: 22.2 years old
Ethnic Groups: Punjabi 44.68%, Pashtun (Pathan) 15.42%, Sindhi 14.1%, Sariaki 8.38%, Muhajirs 7.57%, Balochi 3.57%, other 6.28%
Religion: Muslim 96.4%, other (includes Christian and Hindu) 3.6%
GDP: $523.9 billion (2012 est.)
GDP per capita: $2,900 (2012 est.)
Unemployment: 6.2% (2012 est.)
Timeline: August 16, 1947 - Great Britain gives independence to the Indian subcontinent, splitting it into India, West Pakistan, and East Pakistan (now Bangladesh).
1947-1948 - Pakistan fights its first war against India over control of the Kashmir area.
1965 - Pakistan and India fight their second war over Kashmir.
1971 - Pakistan and India go to war over independence for East Pakistan, later renamed Bangladesh.
1973 - A constitution providing for a parliamentary system of government is adopted.
July 5, 1977 - Prime Minister Zulfikar Ali Bhutto is deposed in a bloodless coup led by the army. He is executed in April 1979.
1985 - Martial law ends, and the parliamentary government is reestablished.
December 1, 1988 - Benazir Bhutto is elected as the first female prime minister of Pakistan and of any Muslim nation.
1991 - Legislation is passed making Islamic law the law of the land.
April 6, 1998 - Pakistan successfully tests a medium-range missile capable of carrying a nuclear warhead On May 28, Pakistan announces it successfully conducted five nuclear tests after detonating a boosted uranium device and four low yield sub-kiloton devices.
May-July 1999 - Pakistan and India engage in a brief war over Kashmir.
October 12, 1999 - General Pervez Musharraf takes power in a bloodless coup. He declares himself president in June 2001.
August 31, 2007 - Musharraf amends the Pakistan constitution to allow himself a third term as president.
September 10, 2007 - Former Prime Minister Nawaz Sharif returns to Pakistan and is deported within hours of landing at the Islamabad airport. He returns to Jeddah, Saudi Arabia.
October 5, 2007 - Musharraf signs a "reconciliation ordinance" that drops outstanding corruption charges against former Prime Minister Benazir Bhutto, opening the way for Bhutto's return to Pakistan and a possible power-sharing agreement between them.
October 6, 2007 - An unofficial vote count indicates Musharraf wins by a landslide in a presidential election almost entirely boycotted by the opposition.
November 3, 2007 - Musharraf declares a state of emergency in Pakistan. He suspends the country's constitution, postpones the upcoming elections and imposes restrictions on the media. Government authorities arrest 1,500 people who protest the state of emergency.
November 9, 2007 - Bhutto is placed under house arrest hours before the start of a protest rally in Rawalpindi, though the arrest warrant is later lifted.
November 11, 2007 - The Pakistani Supreme Court, packed with judges appointed by Musharraf, dismisses five petitions contesting his eligibility as a presidential candidate in the recent elections.
November 28, 2007 - Musharraf steps down as leader of the Pakistani army, the day before he is scheduled to be sworn in as president. General Ashfaq Kayani, appointed vice chief of army staff on October 8, takes over army leadership.
November 29, 2007 - Musharraf takes the presidential oath of office for the third time.
December 27, 2007 - Bhutto is assassinated during a rally in Rawalpindi, Pakistan.
February 19, 2008 - Musharraf's party, the Pakistan Muslim League-Q, admits defeat in Pakistan's parliamentary elections.
March 9, 2008 - Asif Ali Zardari, head of the Pakistan People's Party, and Nawaz Sharif, head of the Pakistan Muslim League-N, sign an agreement making their coalition official. The two leaders call on Musharraf to immediately convene parliament and state they will announce their nominee for prime minister when parliament is called into session.
March 25, 2008 - Yousuf Raza Gilani is sworn in as Pakistan's new prime minister. Gilani is a member of the Pakistan People's Party and served in various capacities as a cabinet member during Benazir Bhutto's terms as prime minister.
April 30, 2008 - After seven hours of talks, leaders from Pakistan's ruling coalition fail to meet their promise to restore to office the judges dismissed by President Musharraf in November, when he declared a state of emergency and dismissed them.
May 12, 2008 - For the second time, Pakistani leaders fail to reach an agreement and meet their self-imposed deadline to introduce a parliamentary resolution restoring the judges. Ex-prime minister Sharif announces that ministers from his party in the federal Cabinet will hand in their resignations the following day.
August 18, 2008 - Pervez Musharraf resigns as president.
September 9, 2008 - Asif Ali Zardari, widower of Benazir Bhutto, is sworn in as the new president.
July-August 2010 - Catastrophic flooding in Pakistan leads to deaths of at least 1,600 people and leaves four million more homeless.