Here are some powerful images from Wednesday's inauguration that symbolize just how unusual and history-making the day's events are.
Global pandemic at the fore
The coronavirus pandemic was inescapably at the fore of Wednesday's events. Instead of crowds in Washington, D.C., the National Mall was empty as well-wishers and supporters were urged to stay home this year and watch the inauguration virtually.
Instead of crowds of people, tens of thousands of American flags waved in the blustery wind Wednesday. The Presidential Inaugural Committee installed nearly 200,000 U.S. flags of varying sizes on a swath of the long, grassy park to represent the American people who cannot attend Biden's inauguration.
The so-called Field of Flags reflects "our commitment to an inclusive and safe event that everyone can enjoy from their home," the committee said.
Moreover, those who could attend this year's ceremonies will be masked up and socially distanced. On Tuesday afternoon, the U.S. passed the grim milestone of 400,000 lives lost to the virus.
Military presence and boarded up businesses
Some 25,000 National Guardsmen from all across America patrolled the nation's capital on Wednesday, creating a military force five times larger than the number of U.S. troops in Iraq, Afghanistan and Syria combined.
The extra security precautions were taken in the wake of pro-Trump supporters conducting a deadly mob attack on the U.S. Capitol building earlier this month during a joint session of Congress. Many businesses in cities across the country were also boarded up Wednesday in the event of further violence breaking out around the inauguration.
Sen. Amy Klobuchar, D-Minn., one of the chairs on the Joint Congressional Committee on Inaugural Ceremonies, referenced the deadly attack on the Capitol during her opening remarks at the inauguration.
"Two weeks ago when an angry violent mob staged an insurrection and desecrated this temple of our democracy, it awakened us to our responsibilities as Americans," Klobuchar said. "This is the day when our democracy picks itself up, brushes off the dust, and does what America always does: goes forward as a nation, under God, indivisible, with liberty and justice for all."
Trump departs early Wednesday, will be absent during ceremonies
In his speech, Trump reflected on his accomplishments over the past four years. Though he did not mention Biden or Vice President-elect Kamala Harris by name, he said he wishes the "new administration great luck and great success." At the conclusion of his speech, Trump pledged, "We will be back in some form."
"Have a good life -- we will see you soon," he told supporters.
Show of unity during Wednesday morning mass
In a contrast with Trump, Biden worked to depict unity and a peaceful transfer of power early Wednesday.
Biden, who often spoke openly about his Catholic faith while campaigning, began the day when he will become president by attending Mass at the Cathedral of St. Matthew the Apostle in Washington, D.C.
He was joined by top congressional leaders from both sides of the aisle -- including House Speaker Nancy Pelosi, outgoing Senate Majority Leader Mitch McConnell, Senate Minority Leader Chuck Schumer and House Minority Leader Kevin McCarthy -- in a show of bipartisan unity.
The future first lady Jill Biden and as well as Kamala Harris and her husband Doug Emhoff also attended the church service Wednesday morning.
Kamala Harris makes history as 1st woman vice president
After more than two centuries of all-male presidents and vice presidents in the U.S., Harris on Wednesday made history as she took her oath of office to become vice president.
The symbolic moment of a glass ceiling being shattered was made even more historic as Harris will also be the first person of Black and South Asian descent in that role.
A diverse nation represented
The inauguration shone a spotlight on America's diversity -- from sight of Harris' mixed family cheering her on to the performers and speakers who took the stage.
Lady Gaga performed the national anthem and Jennifer Lopez sang "America the Beautiful" -- while country singer Garth Brooks, a Republican, did a rendition of "Amazing Grace."
22-year-old Amanda Gorman also stole the show when she recited her original poem, "The Hill We Climb," to rousing applause.
And firefighter Andrea Hall delivered the Pledge of Allegiance aloud and in sign language.
Throughout the ceremonies, the nation's diversity was on display.