White House

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President George Bush and Pakistani Prime Minister Benazir Bhutto stand together during a welcoming ceremony on the grounds of the White House, June 6, 1989. (AP Photo/Bob Daughrety)

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President George Bush shakes hands with South African national leader Nelson Mandela at the White House in Washington, June 25, 1990. (AP Photo/Doug Mills)

President-elect Barack Obama is welcomed by President George W. Bush for a meeting at the White House in Washington, Wednesday, Jan. 7, 2009, with former presidents, from left, George H.W. Bush, Bill Clinton and Jimmy Carter. (AP Photo/J. Scott Applewhite)

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The flag above the White House flies at half-staff in honor of the late South African President Nelson Mandela on Friday, Dec. 6, 2013, in Washington. (AP Photo/Evan Vucci)

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President Obama arrives to speak in the briefing room of the White House in Washington on Thursday, Dec. 5, 2013. (AP Photo/Carolyn Kaster)

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June 21, 2011 "Samantha Appleton, who has since left the White House, photographed the First Lady as she met with former President Nelson Mandela of South Africa at Mandela's home in Houghton, South Africa. (Official White House Photo by Samantha Appleton) This official White House photograph is being made available only for publication by news organizations and/or for personal use printing by the subject(s) of the photograph. The photograph may not be manipulated in any way and may not be used in commercial or political materials, advertisements, emails, products, promotions that in any way suggests approval or endorsement of the President, the First Family, or the White House.