It was a sigh heard round the world. With almost palpable relief, longstanding American allies welcomed Joe Biden as he was sworn in as the 46th president of the United States on Wednesday. Some signaled hopes for a radical change in the White House, particularly in its approach to climate change and the pandemic. And a few took parting shots at Donald Trump and his nationalist, "America first" agenda.

The European Union's top politician, Ursula von der Leyen, said that "after four long years, Europe has a friend in the White House."

"This time-honored ceremony on the steps of the U.S. Capitol will be a demonstration of the resilience of American democracy," she added in a speech in Brussels.

Spanish Prime Minister Pedro Sanchez said that Biden represented "victory of democracy over the ultra-right."

Then he took aim directly at the former president.

Read the story.

Vice President Kamala Harris is already working on the ambitious legislative priorities that Biden is launching Wednesday, notably the immigration legislation, her spokesperson Symone Sanders told NBC News.

With the Senate split 50-50, Harris will be spending a lot of time in the chamber working for immigration and other priorities, including the economic recovery package, health care, climate change and criminal justice reform. 

The vice president has been lobbying her former Senate colleagues for the confirmation of Biden's nominee for secretary of defense, retired four-star Gen. Lloyd Austin, who had his confirmation hearing Tuesday. Austin needs a separate vote to waive a requirement that uniformed military personnel be retired from active service for at least seven years before they take the top defense post, which is supposed to be a civilian job.

Harris is already in the Senate and will be handling the first order of business, swearing in the three new senators — Raphael Warnock and Jon Ossoff, both Democrats from Georgia, and Alex Padilla, Harris' Democratic replacement from California.

Biden stopped near the end of the inaugural parade to speak with — and fist bump — "Today" show weather anchor Al Roker and, separately, NBC News' Mike Memoli.

"It feels great!" Biden shouted back at Roker when asked how it felt to finally become president. The 46th commander in chief, who was about to walk into the White House, told Memoli when asked a similar question, "Feels like I am going home."

Dr. Rochelle P. Walensky, who on Wednesday took over as the director of the Centers for Disease Control and Prevention, said the agency will be evaluating all existing government guidance instituted under the Trump administration related to Covid-19. 

"Just as it has since the beginning of the pandemic, CDC will continue to focus on what is known — and what more can be learned — about the virus to guide America," Walensky said in an introductory statement.

"As part of that promise, CDC’s Principal Deputy Director Anne Schuchat will begin leading a comprehensive review of all existing guidance related to COVID-19," she said. "Wherever needed, this guidance will be updated so that people can make decisions and take action based upon the best available evidence."

Walensky's position is an appointment and therefore does not require Senate confirmation. She previously served as chief of the division of infectious diseases at Massachusetts General Hospital. 

As Joe Biden and Kamala Harris were sworn in as president and vice president Wednesday, the internet was at the ready to capitalize on every funny or strange moment in an otherwise serious and storied event.

With attendees abiding by Covid-19 guidelines and social distancing, the images of the inauguration differed from years' past, leading some to pounce on an opportunity to joke about politicians looking cold and alone at the event.

Others teased the appearances and performances of singers Lady Gaga and Jennifer Lopez.

While most of the memes were meant to be humorous, some used a format popularized in 2020 to create heartfelt memes, showing just how far some at the inauguration had come.

First came the debate memes. Then came the election memes.

Finally, here's our list of the best inauguration memes.

Pope Francis extended his "good wishes" to Joe Biden on his inauguration, and called on God to help the new president heal a polarized nation and world.

"Under your leadership, may the American people continue to draw strength from the lofty political, ethical and religious values that have inspired the nation since its founding," he said in a message issued by the Vatican's press office. 

Francis added: 

"At a time when the grave crises facing our human family call for farsighted and united responses, I pray that your decisions will be guided by a concern for building a society marked by authentic justice and freedom, together with unfailing respect for the rights and dignity of every person, especially the poor, the vulnerable and those who have no voice. I likewise ask God, the source of all wisdom and truth, to guide your efforts to foster understanding, reconciliation and peace within the United States and among the nations of the world in order to advance the universal common good."

Kamala Harris, the daughter of an Indian mother and a Jamaican father — both immigrants — broke a nearly two-century barrier in American politics long dominated by white men on Wednesday when she was inaugurated as the nation's first female vice president, as well as the first Black American and first person of South Asian descent.

Her swearing-in was laced with the historic nature of the day.

The oath of office was administered by Supreme Court Justice Sonia Sotomayor, the first Latina member of the high court. Harris swore on two bibles, one belonging to Regina Shelton, a close family friend, and the other once owned by Thurgood Marshall, the first Black Supreme Court justice. Harris often says that Marshall inspired her to become a lawyer.

Harris also wore an outfit designed by Christopher John Rogers and Sergio Hudson, both of whom are Black and from the South, a region pivotal to the Biden-Harris ticket's win. (Rogers is from Baton Rouge, Louisiana, and Hudson is from South Carolina.) Her fashion choice tracks with the value that Harris said her mother instilled in her: “You may be the first to do many things. Make sure you’re not the last.”

Read the story.

President Joe Biden was elected on a promise to restore normality, but his presidency began Wednesday with a most unusual swearing in, with most of the pomp stripped away by the necessity of circumstance.

The day did not go as inaugurations of past have happened. The mall did not buzz with exuberant crowds; the streets did not teem with parade spectators; and the city's ballrooms were not adored with sequined gowns.

But it happened, nonetheless, which may be the only thing that matters at a moment when America’s democratic institutions have been tested, almost to the breaking point.

"Democracy is precious. Democracy is fragile,” the new president said after taking the oath on his family’s 127-year-old Bible. “And at this hour, my friends, democracy has prevailed.”

Read the story.

The Trump appointee overseeing the Voice of America and other U.S.-funded broadcasters resigned on Wednesday at the request of the Biden administration, after a tumultuous tenure marked by accusations he was undermining the networks' editorial independence.

Michael Pack, CEO of the U.S. Agency for Global Media, said his resignation ws effective at 2 p.m. EST, just two hours after Joe Biden became the 46th president of the United States, according to an email sent by Pack to staff.

Pack came under fire from both sides of the aisle in Congress, from press freedom groups and from current and former journalists at Voice of America and other outlets over a spate of decisions that critics said were designed to turn the broadcasters into mouthpieces for the Trump administration.

"I serve at the pleasure of not one particular president, but the office of the president itself. The new administration has requested my resignation, and that is why I have tendered it as of 2PM today," Pack wrote to the staff.

Read the story.

Several years ago, former Pawnee, Indiana, City Councilwoman Leslie Knope received congratulations from then-Vice President Joe Biden during an episode of NBC's Parks and Recreation.

Today, the show confirmed she's happy for President Biden too.