U.S. President Barack Obama takes the oath of office again Monday at a public ceremony in front of the Capitol building, where he will also give an address before taking part in a parade to mark the beginning of his second term.
As many as 800,000 people are expected to crowd the National Mall to witness the event. That is a smaller number than his first inauguration when nearly 2 million people came to see the swearing-in of the nation's first black president.
Mr. Obama took the official oath of office Sunday because the U.S. Constitution mandates the president be sworn in on January 20. Chief Justice John Roberts administered the oath, just as he did for the president in 2009.
Mr. Obama will retake the oath Monday using two historic Bibles - one owned by 19th-century president Abraham Lincoln, and the other by civil rights leader Martin Luther King Jr., who was assassinated in 1968.
Monday's inauguration coincides with the federal holiday marking King's birthday.