Joe Biden has been sworn in as the 46th President of the United States and has declared "a new day for America".
"Democracy has prevailed" he told the crowd after taking the Oath of Office.
He identified key challenges for the new administration as "a once in a century virus which now stalks the country" and "a cry for racial justice".
"I will be a President for all Americans," he said.
Earlier, in a massive security clampdown prompted by the January 6 invasion of the US Capitol building by Donald Trump supporters, only about 2000 spectators were allowed. They are vastly outnumbered by the police, Secret Service and 25,000 members of the National Guard watching for any attempt to stop the peaceful handover of power.
The traditional inauguration parade, luncheon and ball have been cancelled, replaced by a virtual parade with acts from around the US and a national TV special. But the inauguration ceremony still has some star power - Lady Gaga will sing the national anthem and Jennifer Lopez is also performing.
We'll keep you updated here throughout the day with live video and a live blog, breaking news as it happens and reaction from Herald columnists, including our man in Washington, Dick Brass.
His term at an end, President Donald Trump has said farewell to Washington, but he also has hinted about a comeback despite a legacy of chaos, tumult and bitter divisions in the country he led for four years.
Trump spoke to supporters at Joint Base Andrews in Maryland where he walked across a red carpet and boarded Air Force One to head to Florida.
He said: "So just a goodbye. We love you." And the 45th president added, "We will be back in some form."
Trump departs office as the only president ever impeached twice, and with millions more out of work than when he was sworn in and 400,000 dead from the coronavirus.
When and where is Joe Biden's inauguration ceremony?
In keeping with tradition, the inauguration will be held on January 20. The inauguration is expected to begin at 11am (5am NZT). He will be sworn in on the steps of the US Capitol in Washington DC.
Biden will be required to take an inaugural oath before assuming his duties and will deliver a public address. The President-elect and vice-president, Kamala Harris, will also give interviews.
Will the ceremony be held behind closed doors?
Festivities are being scaled back, with public health measures including mandatory masks, temperature checks and social distancing in place. Barack Obama's inauguration in 2009 - when Joe Biden became Vice President - was attended by approximately two million people.
By contrast, the Biden-Harris team has announced that celebrations will be "extremely limited" in size, and viewing stands along the parade route have been dismantled.
Following the violence seen on January 6, the entire Washington Mall has been closed to the public for the event, according to reports from the Washington Post. The Mall is the site where supporters traditionally gather to watch proceedings.
This year, the Mall will only be open to security personnel and the media. It will reopen to the public on January 21.
The mayor of Washington DC, Muriel Bowser, has extended a public emergency declaration until January 21, the day after inauguration. This order empowers officials to reduce the hours of operation for businesses, order people off the street if a curfew is issued, and expend funds as needed to protect public safety, suggesting that city officials have the power to prevent people from gathering for the event.
Following the attacks, the DC National Guard will also be on hand, having been mobilised for 30 days from January 6.
Then, on January 18, fears were further heightened, when an inauguration rehearsal was interrupted by a false alarm, as plumes of smoke were detected near the Capitol building. In the rehearsal, spectators were ushered from the west front of the Capitol, while the officials declared it was "not a drill".
However, it later emerged that the smoke was from a fire in a homeless encampment approximately 1,6km away.
Who is performing at Biden's inauguration ceremony?
Lady Gaga and Jennifer Lopez will take the stage at the inauguration ceremony, alongside others in what his transition team said would showcase a diverse America.
Other performers include Justin Timberlake, Jon Bon Jovi, Demi Lovato and Ant Clemons.
Foo Fighters, John Legend and Bruce Springsteen will offer remote performances, and Eva Longoria and Kerry Washington will introduce segments of the event.
Despite a raging pandemic forcing most performances online, it is a sign that Hollywood is back and eager to embrace the new president-elect four years after many big names stayed away from the inauguration of Donald Trump.
The event will also feature remarks from a black firefighter from Georgia, a former Youth Poet Laureate, a Catholic priest, and a pastor from Biden's hometown of Wilmington, Delaware.
Lady Gaga will sing the national anthem and Lopez will give a musical performance.
"They represent one clear picture of the grand diversity of our great nation," Biden's team said in a statement.
What will Joe Biden say?
Every president since George Washington has delivered the Inaugural Address. Trump spoke for 16 minutes during his vow to break the "established order" and "make America great again".
For Biden, the focus is likely to be on the cornerstones of his policies: the pandemic, the economy, climate change and health care.
It also seems likely he will touch upon the issue of uniting Americans again - whether they voted for him or not. Unity has already been a key theme of his commentary so far.
"With the campaign over, it's time to put the anger and the harsh rhetoric behind us and come together as a nation," Biden said in a statement. "It's time for America to unite."
Biden has also unveiled a US$1.9 trillion plan to tackle the coronavirus pandemic, boosting financial aid for Americans and businesses.
When will Trump leave the White House and when will the Bidens move in?
Biden and his wife, Dr Jill Biden, will move into the White House on January 20, following the inauguration ceremony.
Trump acknowledged his defeat for the first time on January 7, confirming that he would leave the White House before Inauguration Day.
Trump has confirmed he will not attend the ceremony and is expected to fly to his Florida property of Mar-a-Lago this morning.
He tweeted on January 8: "To all of those who have asked, I will not be going to the inauguration on January 20th."
As a result, Trump will be breaking a decades-long tradition. He will be the first president in more than 150 years - and just the fourth in US history - to miss the event. Usually, the person departing the White House would welcome their predecessor to the Oval Office and attend the swearing-in ceremony.
What time is Joe Biden's virtual inaugural parade?
Joe Biden's inaugural parade is projected to take place around 2-3pm (8-9am NZT).
With strict measures in place to comply with Covid safety procedures, the event will take place largely online. In-person attendance of the event will be limited.
What else is happening on Inauguration Day?
Traditional inaugural events have been largely scaled back this year due to the pandemic and security concerns, following the recent riots.
Tom Hanks will host a 90-minute TV special, Celebrating America, which will air right after the swearing-in ceremony.
Why is there a gap between the election and presidential inauguration?
The election was held on November 3, 2020, but Biden does not officially become president until over two months later.
Until 1933, the new president was inaugurated on March 4, four months after election day. This was then shortened to around two months with the ratification of the 20th Amendment.
The time between US election and inauguration allows for the incumbent to tie up any loose ends, and for the incoming president to prepare for his tenure by working on policy and appointing his cabinet.
And what about Kamala Harris?
Vice president-elect Kamala Harris will take the inaugural oath, but before Biden. Harris will be the nation's first female vice president.
She will swear to "support and defend the Constitution" and "faithfully discharge the duties of the office".
- Daily Telegraph