A boy scout hands out flags as dawn breaks in America's capital. A day of celebration for many, but will the new president be able to meet the high expectations?
One of Barack Obama's many supporters shows her pride in making it to Washington's National Mall for the inauguration of the 44th American president.
A US Air Force Honour Guard keeps watch near the US Capitol building in Washington. Massive security was in place, with 40,000 security personnel either on duty or on stand-by.
At least two million people are said to have turned up for the ceremony - many arriving in the early hours of the morning. It was pretty chilly though, with temperatures below freezing.
George W Bush and his wife Laura pose at the White House with Mr Obama and his wife, Michelle. The outgoing president is moving back to his ranch in Texas.
Another supporter shows off her customised Obama gloves. The new president convincingly beat his Republican rival John McCain in November's election.
Celebrations for the new president also took place in some parts of the UK. This woman was pictured getting into the spirit at an arts centre in Tottenham, north London.
Obama's big day was also big news in Kenya - his dad was born there and many Kenyans see him as one of their own. Obama's mother, a white woman from Kansas, met his father at university.
Barack Obama takes the oath of office and is sworn in as America's 44th president. Placing one hand on the bible he promises to "preserve, protect and defend" the US constitution.
There is much optimism for the future as America's first African-American leader takes office. He is charged with an economy facing its worst crisis in decades, as well as wars in Iraq and Afghanistan.