The inauguration of Barack Obama as the 44th President of the United States took place on Tuesday, January 20, 2009. The inauguration marked the commencement of the four-year term of Barack Obama as President and Joseph Biden as Vice President. Based on combined attendance numbers, television viewership and Internet traffic, it was among the most observed events ever by the global audience.
"A New Birth of Freedom", a phrase from the Gettysburg Address, served as the theme for the inauguration to commemorate the 200th anniversary of the birth year of Abraham Lincoln. In his speeches to the crowds, Obama referred to ideals expressed by Lincoln about renewal, continuity and national unity as he stressed the need for shared sacrifice and a new sense of responsibility to answer America's challenges at home and abroad. Obama and others paid homage to Lincoln in the form of tributes and references during several of the events, starting with a commemorative train tour from Philadelphia, Pennsylvania to Washington, D.C. on January 17, 2009. The inaugural events held in Washington, D.C. from January 18 to January 21, 2009 included concerts, a national day of community service on Martin Luther King, Jr. Day, the swearing-in ceremony, luncheon and parade, inaugural balls, and the interfaith inaugural prayer service. In addition, a philanthropist organized a "People's Inaugural Ball" for disadvantaged people who otherwise would be unable to afford to attend the inaugural festivities and the Presidential Inaugural Committee hosted the Neighborhood Inaugural Ball with free or affordable tickets for ordinary citizens.