Bernie Sanders, who lost out to President Joe Biden during the Democratic primaries, is no stranger to social-media stardom.

Now an AFP photographer's snap of him bundled up for the brisk weather in Washington DC today is the latest image of the veteran senator to go viral and become a meme.

His outfit has been getting a lot of love, but it's the knitted mittens he was spotted wearing that are getting the most attention.

They've been trending online and according to reports, were actually given as a gift to him by a teacher named Jen Ellis from his home state of Vermont a couple of years ago.

She made them from recycled jumpers and sent 10 pairs as a gift to his campaign to show him her support - sharing her excitement with a local news website last year, external after they were spotted in hand-warming action on the campaign trail.

Responding to the online gossip about his attire, Sanders told CBS: "In Vermont we dress warm. We know something about the cold.

"And we're not so concerned about good fashion. We want to keep warm. And that’s what I did today.”

Former presidents Barack Obama, George W Bush and Bill Clinton - along with their first ladies - joined President Biden and Vice-President Harris at Arlington National Cemetery.

The past and present presidents took part in a moment of silence and a ceremonial laying of the wreath at the Tomb of the Unknown Soldier.

Image source, Reuters

Zhaoyin Feng
BBC Chinese, Washington DC

Image source, Getty Images

China certainly will not miss Donald Trump.

Beijing waved goodbye today by sanctioning 28 Trump officials only minutes after Joe Biden was sworn in.

Among those that are no longer welcome inside China is ex-secretary of state Mike Pompeo, and ex-health secretary Alex Azar.

The parting shot signals that the new president will face an uphill battle regarding US-China relations, arguably the biggest foreign policy challenge facing the US.

Beijing’s foreign policy spokeswoman Hua Chunying said today that China hopes the Biden administration will conduct “more win-win co-operation” with China “in the spirit of mutual respect”.

Many in Washington are concerned that “win-win” means China wins twice.

There will be huge pressure from Congress to maintain at least some hardline policies towards China, urging the country to change its unfair trade practices and to end human rights violations. However, torpedoing US-China relations could lead to a global catastrophe.

Biden didn’t mention China in his inaugural speech, but he did send a message to China and the rest of the world that America would not “turn inward”.

One of Biden’s daunting tasks in re-engaging with the world will be leading the US to challenge and coexist with an increasingly influential China.

Image source, Getty Images

The cemetery - just across the river from Washington DC - is home to the graves of dead US troops dating back to the Civil War.

It is also the final resting place of two presidents - John F Kennedy and William H Taft.

The land was seized from Confederate general Robert E Lee during the Civil War, and has since become home to the remains of over 400,000 men and women.

Presidents Bill Clinton, George W Bush and Barack Obama will join the new president and vice-president for a wreath-laying ceremony and a moment of silence.

The Tomb of the Unknown Soldier, where the wreath-laying will take place, is one of the most visited parts of the cemetery.

Entombed there are the remains of soldiers from World War I, World War II, the Korean War and the Vietnam War.

The presidential motorcade has just arrived at Arlington National Cemetery in Virginia.

Troops are carrying out a 21-gun salute there to mark the new president's inauguration.

Biden and Harris, as well as former Presidents Bush, Clinton and Obama and their spouses, will lay a wreath at the Tomb of the Unknown Soldier.

Mark Savage
Music reporter, BBC News

Donald Trump could often be found dancing to the Village People's disco anthem YMCA at his rallies - but Joseph Biden referenced a very different song in his inaugural speech.

The new president read out a verse of Gene Scheer's American Anthem, describing it as "a song that means a lot to me".

"The work and prayers / Of centuries / Have brought us to this day / What shall be our legacy? / What will our children say?

"Let me know in my heart /When my days are through /America, America / I gave my best to you"

Although it sounds timeless, the song was actually written in the late 1990s.

It premiered in 1999 at the Smithsonian Institution's unveiling ceremony for the restored "Star-Spangled Banner" - the flag that inspired Francis Scott Key to write the song that would become America's national anthem.

Scheer said the "spark" for his song was lit by reading a book about the drafting of the US Constitution. "I was just so inspired that it started making me think about all we'd been given by our forefathers," he told NPR in 2004, external.

American Anthem has subsequently been played at several presidential inaugurations. But it achieved widespread popularity after jazz singer Norah Jones sang a stripped-back, emotional version of the song for Ken Burns' World War 2 documentary series, The War in 2007.

Anthony Zurcher
BBC North America reporter

Three Supreme Court justices appear to have skipped Joe Biden’s inauguration - Stephen Breyer, Samuel Alito and Clarence Thomas. There has been considerable speculation that the liberal Breyer, at age 82, may retire soon, allowing Biden and the Democratic-controlled Senate to seat his successor.

Alito is one of the more conservative members of the court, who visibly mouthed “not true” when Barack Obama criticised a court decision during one of his State of the Union addresses.

Clarence Thomas and Biden have a particularly fraught history, as the then-senator from Delaware chaired Thomas’ Supreme Court confirmation hearings in 1991. Those hearings became a national spectacle when Anita Hill publicly accused the nominee of sexually harassing her in a previous government workplace. Thomas described the experience as a “high-tech lynching”.

After Thomas criticised his confirmation process and, indirectly, Biden in a recent documentary, Bill Russo - a Biden aide - told ABC in a statement: “Then-senator Biden voted against Clarence Thomas in the Senate Judiciary Committee, he argued against him on the Senate floor, and he voted against his confirmation to a lifetime seat on the Supreme Court. It is no surprise that Justice Thomas does not have a positive view of him.”

Image source, Reuters

Joe Biden has left the US Capitol, en route to Arlington to lay a wreath.

He and his wife Jill stepped into a vehicle with the registration plate 46 - he is the 46th US president

Lyse Doucet
Chief International Correspondent

Image source, Getty Images

Afghanistan hasn’t dominated debate on American foreign policy. But, for better or worse, Afghanistan is in President Biden’s diary.

The 2020 deal with the Taliban sees the US pulling out the last of its troops by May.

Biden wants to end America’s longest war. But his commanders on the ground, Nato allies, and many others, still worry about whether the Taliban are able and willing to cut ties with the al-Qaeda terror group, and cut a peace deal with Afghans.

There’s much talk of, at the least, a little delay.

The worst fear is a “fighting season” like no other this summer. That’s no way for the US to leave. It’s no way for the US to mark the 20th anniversary of the September 11th attacks which sent US troops in.

And it’s no way to ensure Afghanistan stands a chance of avoiding a descent into a war which would ripple across the region and far beyond.

The new president and vice-president have just walked out of the Capitol to review the troops on the East Front.

The motorcade is standing by ready to take them to Arlington National Cemetery for a wreath-laying ceremony after that.

The Joint Committee on Inaugural Ceremonies has just presented gifts to newly sworn-in President Biden and Vice-President Harris at a ceremony in the rotunda.

Republican Senator Roy Blunt presented the duo with a landscape painting by an Ohio artist once hailed as "the best landscape painter in the West".

Democratic Senator Amy Klobuchar handed the incoming administration two crystal vases that "represent the hope and faith the American people have placed in you to move the country forward".

Congressional leaders also presented gifts to Biden and Harris, from flags that flew over Congress to framed photos of iconic moments in American history.

Tara McKelvey
BBC News, Washington

Law enforcement authorities have been monitoring extremist threats and the US military has flooded the zone.

Yet, shortly after the new president was sworn in, the heavily barricaded streets near the White House remained quiet.

One of the people guarding the district - Will Hart, of Andalusia, Alabama - was cooking ramen noodles over an open flame on E Street, with an automatic rifle perched nearby.

Back in Alabama, he says, he is learning how to be a welder. Here, he is carrying 80-90 pounds of kit and is ready for anything.

When I point out that the neighbourhood is completely quiet, with none of the problems that were anticipated, he nods patiently.

“Wait till tonight,” he says, with a smile.

Republican strategist Seth Weathers has been talking to the BBC about the legacy Trump leaves behind, and says that he's changed the Republican party for good.

"This November, Trump received more votes than any [incumbent] presidential candidate in history," said Mr Weathers. "Any Republican going forward is going to need to have a very good thought about going with 'America First' policies as the president did."

Mr Weathers also pointed to Trump's success with the US economy before the coronavirus pandemic, and peace deals struck in the Middle East.

He dismissed allegations that Trump had incited the riots which took place in Washington earlier this month, and called the president's two impeachments a "sham".

"The reality is that there is literally no basis for the [impeachment] that's happening now."

Post-presidency, Mr Weathers says he doesn't believe Mr Trump will run again in 2024, but instead he'll play the role of "kingmaker".

He's also heard from people close to the president that Mr Trump is considering whether to start his own social media platform to rival firms like Twitter.

A short while ago, Amanda Gorman became the youngest poet to write and recite a piece at a US presidential inauguration.

Social media is ablaze with praise for the 22-year-old's stirring composition.

One reaction that caught Gorman's eye came from Lin-Manuel Miranda, the creator of the smash hit Broadway musical Hamilton.

If you missed it, you can watch Gorman's powerful reading of The Hill We Climb below.

The new president and vice-president are inside the US Capitol having taken their oaths of office.

They are taking part in a signing ceremony inside - Joe Biden has signed the Inauguration Day proclamation and nominations for his cabinet and sub-cabinet.

Biden and Harris will soon review the readiness of troops, as per tradition, just outside the Capitol.

After that President Joe Biden and Dr Jill Biden will depart for Arlington National Cemetery, where, accompanied by former Presidents Bush, Clinton and Obama and their spouses, they will lay wreaths at the Tomb of the Unknown Soldier.

After that the new president will be escorted to the White House by the military, where members of an honour guard are awaiting Joe Biden's arrival.

Image source, Reuters

Kamala Harris, as the new president of the Senate, will take part in the swearing in of three new senators - her replacement from California and two newly elected Democrats from Georgia.

This will be the moment control of the upper house shifts from Republican to Democrat.

Image source, Reuters

Former President Donald Trump touched down in Florida shortly before the inauguration ceremony got under way.

Crowds of supporters met him on his arrival, lining the streets with signs with slogans including "Still my president" and "Trump won".

Mr Trump then spent his final 30 or so minutes as president inside his Mar-a-Lago golf resort in Palm Beach.

He is back to being, at least for now, a private citizen but with a Senate impeachment trial looming.

Image source, Reuters

Marianna Spring
Disinformation and social media reporter

The idea that the 2020 election was somehow “stolen” or “rigged” dominated the last days of Donald Trump’s presidency.

But his departure speech earlier – unusually - offered few breadcrumbs to those who believe in such conspiracy theories.

Huge groups organising online under the banner “Stop the Steal” took their lead from the former president, and a series of demonstrations led to that deadly riot on 6 January.

With additional security surrounding today’s events, some experts tell me that a greater concern is that individuals – or “lone wolves” – take action, rather than another mass mob.

Those energised, and even radicalised, by conspiracy groups will remain. And even if the theories about a “stolen” election start to fade, the damage done to trust - in democracy, in experts, in authority - will take a long time to repair.

Gabriel is a member of our election voter panel.

He is writer and serves as the activism chair for the New York Young Republicans.

He wishes the Biden administration good luck, but is concerned it will sow more division in a vulnerable moment for the country.

What are your hopes for Biden?

As an American, I am hopeful that things go well under this administration. I don't wish for Joe Biden to fail because the president is like the pilot of a plane: if he goes down, so do we. I hope he can answer the renewable energy debate, create more nuclear power plants and allow the United States to remain the number one exporter of energy. Hopefully, we'll see some sort of voter ID laws enforced, for greater election integrity. I hope he doesn't fuel more divisions.

Reality Check

President Biden has promised to tackle political extremism during his speech at the Capitol building - which was itself stormed by rioters including far-right groups and those supporting baseless conspiracy theories earlier this month.

“And now, the rise of political extremism, white supremacy, domestic terrorism, that we must confront and we will defeat,” said Mr Biden.

The US Department of Homeland Security has warned that violent white supremacy is the "most persistent and lethal threat in the homeland".

And experts say that far-right groups, many of which gravitated towards former President Trump, are an increasing threat.

The Armed Conflict Location & Event Data Project (ACLED) says such groups have been increasingly active in demonstrations against the outcome of the US presidential election in November.

Demonstrations are also more likely to turn violent if militia members are present, ACLED says.

Find out more here.

Image source, Reuters

Although mask-wearing was almost ubiquitous at today's inauguration ceremony, some watching the events have taken to social media to complain about the lack of social distancing between senior figures.

Many former presidents, their families, and performers were all seen embracing and shaking hands at points during the ceremony.

Some social media users defended the actions - pointing out that many of the high-profile figures will have been tested prior to the event and some have been vaccinated already.

Both others criticised their behaviour, saying it was sending a mixed message to the public - especially after widespread criticism towards the Trump administration for holding events where the virus is suspected to have spread.

The US Centers for Disease Control and Prevention (CDC) tells people to avoid crowds and stay at least 6ft away from people outside of their household - even outside.

Image source, Reuters