Barack Obama swept to victory as the first black president in the US history Tuesday night in an electoral college landslide that overcame racial barriers as old as America itself.

In his first speech as president-elect, Obama catalogued the challenges ahead. "The greatest of a lifetime," he said, two wars, a planet in peril, the worst financial crisis in a century.

The son of a black father from Kenya and a white mother from Kansas, the Democratic senator from Illinois sealed his historic triumph by defeating Republican Sen. John McCain in a string of wins in hard-fought battleground states -- Ohio, Florida, Virginia, Iowa and more.

Obama, 47 will be sworn in as the 44th US president on January 20, 2009. He will face a crush of immediate challenges, including easing the economic crisis, ending the war in Iraq and striking a compromise on overhauling the health care system.