Barack Obama took the oath of office just before noon in Washington on Monday to begin his second term as president of the United States. Supreme Court Chief Justice John Roberts administered the oath to the president on a platform on the steps of the U.S. Capitol with hundreds of thousands of flag-waving citizens viewing the inaugural ceremonies from the National Mall.

In his second inaugural address, Obama set an agenda for his next four years in the White House and urged citizens and lawmakers to come together to address the issues facing the nation.

"We have always understood that when times change, so must we, that fidelity to our founding principles requires new responses to new challenges, that preserving our individual freedoms ultimately requires collective action," Obama said.

Among the actionable items included in the nearly 20-minute-long address were school and tax reform, education and technology investment and the fortification of the middle-class.

"For we, the people, understand that our country cannot succeed when a shrinking few do very well and a growing many barely make it," he said. "We believe that America's prosperity must rest upon the broad shoulders of a rising middle class."

The president also addressed more progressive ideals such as the extension of social programs, climate change, the gender pay gap and gay rights.

"Our journey is not complete until our gay brothers and sisters are treated like anyone else under the law, for if we are truly created equal, then surely the love we commit to one another must be equal, as well," he said.

The speech also noted the anticipated end of a "decade of war" and the economic recovery that commenced despite the recession at the beginning of Obama's first term.

Obama took the oath with his wife, Michelle, holding Bibles — one from Abraham Lincoln, the other from Martin Luther King Jr. — atop which the president placed his hands. Daughters Malia and Sasha observed nearby.

Monday is also the federal holiday which commemorates the birthday of King, the civil rights' leader who was assassinated in 1968.

Vice President Joe Biden was sworn in for a second term by Justice Sonia Sotomayor just prior to Obama taking the oath. Sen. Charles Schumer (D-NY) served as emcee.

Two official Inaugural Balls and other events were scheduled for the remainder of the day in Washington.

Monday's events were ceremonial; Obama's second term officially began when he took the oath from Roberts inside the White House at noon on Sunday, Jan. 20, as stipulated in the U.S. Constitution.

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