Barack Obama strode to the pinnacle of American power on Tuesday, taking the oath as the 44th US president and shattering racialu00a0barriers as the first black leader of the country.

He took over a nation longing for change after President George W Bush's eight divisive years in the White House, an era that witnessed the Sept 11, 2001 terror attacks, the beginning of wars in Afghanistan and Iraq and an economic collapse not seen since the 1930s Great Depression.