Washington - Hundreds of thousands of spectators have begun gathering in Washington to watch the 44th President of the United States of America, Barack Obama, and Vice-President Joseph Biden take their oath on the western steps of the Capitol.
The two will take an oath of allegiance to the Constitution and the country at around 11.30am local time.
The Inauguration Day is to begin for Mr Obama, 47, with a morning service at one of the capital's churches, the name of which has not been disclosed in advance by his aides and the US Secret Service agents for security considerations.
Then, at 9:55am, the US President-elect together with his wife Michelle will arrive at the White House, where they will be greeted by President George W. Bush at the main entrance under the vaults of the so-called Northern Portico.
Mr Biden and his wife and the leaders of the Joint Congressional Committee on Inaugural Ceremonies will also arrive at the presidential residence.
At 10:45am the presidential motorcade will ride from the White House to the Congress building on Capitol Hill, where the inaugural ceremony is to begin at 11:30am. At that moment Mr Obama and Mr Biden are to mount the raised platform accompanied by the Chiefs of Staff of the Senate and the House of Representatives.
The ceremony will open up with two music items to be performed by the orchestra of the US Marine Corps and children's choirs of boys and girls from San Francisco.
Then Senator Dianne Feinstein, Chairperson of the Joint Congressional Committee on Inaugural Ceremonies, will address the crowds. After her speech Rick Warren, Dean of the Episcopal Church, will say a prayer, followed by singing by "soul music queen" Aretha Franklin.
At 11:46am Mr Biden will be sworn in. The oath is to be administered by Supreme Court Member John Paul Stevens. Thereafter Mr Obama will be sworn in. He will take the oath of office, raising his right hand and putting his left hand on the Bible.
The oath is to be administered by John Roberts, Chief Justice of the Supreme Court.
The festivities are to end with an inaugural address by Mr Obama at around noon and the playing of the national anthem.
In accordance with Article 2 of the Constitution, a president is bound to take the following oath: "I do solemnly swear and affirm that I will faithfully execute the office of President of the United States, and will, to the best of my ability, preserve, protect, and defend the Constitution of the United States".
The words "and so help me God" have been added to the traditional formula.
According to the tradition established by George Washington at the first inaugural ceremony in the Federal Hall in New York on 30 April, 1789, a president takes an oath on the Bible, although this is not stipulated in the Constitution.
For his inauguration, Mr Obama chose the Bible on which Abraham Lincoln had taken an oath in 1861. In general, Mr Obama in many respects follows the ways of his great predecessor, the bicentenary of whose birth is to be marked in the United States throughout this year.
The quotation from Lincoln's famous Gettysberg Address, "The New Birth of Freedom" has become the general theme of the present-day festivities.
After the inaugural address, Mr Obama will head to the Hall of Statues in the Capitol Building where a lunch is to be given in his honour.
A parade from the Capitol, along the Pennsylvania Avenue, and to the White House will begin at 2pm and it will last three hours. The presidential limousine will lead the festive parade.
Upon returning to the White House, Mr Obama and his wife are to mount a specially erected rostrum protected with bulletproof glass, to greet the parade participants.
At 7pm. the president will leave the White House and together with the First Lady will go to inaugural balls, of which there will be ten this year.
The presidential couple intend to attend if only for a while, all of them. The festivities will continue deep into the night and the president and his wife will return to the White House only at dawn on 21 January.
