Donald Trump is set to be sworn in as the 45th president of the United States.
Over hundreds of thousands of supporters and protesters have travelled to Washington DC for the event.
The property tycoon, who is never known for his religiosity, attended church on Friday, and has stacked his inauguration with more clergy than any other.
Thousands of police were deployed with many kilometres of crowd barriers set up as part of a vast security operation.
Speaking to supporters on Thursday night at a pre-inaugural concert, Mr Trump pledged to unify America, bring change and make the country great “for all of our people”.
Demonstrations for and against Mr Trump include a rally for the new president by Bikers for Trump after the ceremony.
The Women’s March on Washington on Saturday – for racial and gender equality, and other issues perceived to be under threat from Mr Trump’s administration – is expected to draw about 200,000 people.
Mr. Trump, who will be sworn in as the 45th president within hours, went to the White House to meet with President Obama, the 44th.
As Mr. Trump prepares to assume the presidency, he and his senior aides have settled on a strategy to begin slowly unwinding regulations and policies from the Obama era, opting against the more sudden approach that some inside his team had recommended.
The plan, as described by one senior Trump official, is “more rolling thunder than shock and awe.”
Some aides to Mr. Trump, including his chief strategist, Stephen K. Bannon, had advised the president-elect to make a more dramatic show of his first few days in office, by signing a flurry of executive orders and making new policy pronouncements that would undo many of Mr. Obama’s actions on immigration, wages, banking and the environment.
But Mr. Trump has opted instead to let his plans trickle out over the next 30 days, this official said.