Past, present and future presidents of the United States have met at the White House.
Barack Obama said he hoped to learn from his predecessors as he met outgoing President George Bush on Wednesday and three former presidents: Bill Clinton (1993-2001), George Bush (1989-93) and Jimmy Carter (1977-1981).
It was the first such meeting at the White House since 8 October, 1981, when the death of Egyptian President Anwar al-Sadat saw a gathering of Richard Nixon, Gerald Ford and Mr Carter with then-president Ronald Reagan.
White House spokeswoman Dana Perino called it "a historic gathering."
It was the second time Mr Obama has visited the White House since his election. Mr Bush hosted the incoming president on 10 November.
Mr Obama takes over on 20 January.