The Most Moving Photos from Tuesday Night's COVID Memorial in Washington, D.C.

Hours after the United States surpassed 400,000 deaths from the novel coronavirus (COVID-19) pandemic, and as vaccine distribution continued across the country, the country's next leaders marked the grim milestone with a memorial service in the nation's capital on Tuesday night.

At a solemn ceremony at the Lincoln Memorial Reflecting Pool in Washington, D.C., President-elect Joe Biden and Vice President-elect Kamala Harris — joined by spouses Dr. Jill Biden and Doug Emhoff — took turns memorializing COVID-19's American victims.

Biden, in a brief speech, drew on his own history of loss.

"To heal, we must remember. And it is hard sometimes to remember, but that's how we heal," he said. It is important to do that as a nation. That is why we are here today."

As he went on, the lights around the pool alit. "Between sundown and dusk, let us shine the lights in the darkness along this sacred pool of reflection and remember all who we have lost," he said.

Harris echoed that in her own remarks.

"We gather tonight, a nation in mourning, to pay tribute to the lives we have lost: a grandmother or grandfather who was our whole world; a parent, partner, sibling or friend who we still cannot accept, is no longer here," Harris said. "And for many months, we have grieved by ourselves."

"Tonight," she said, "we grieve — and begin healing — together."

The reflecting pool was lit to "honor those who have died" throughout the ongoing pandemic, the Presidential Inaugural Committee previously said.

During the event, from the foot of the Lincoln Memorial, nurse Lori Marie Key sang "Amazing Grace," performer Yolanda Adams sang Leonard Cohen's "Hallelujah" and Cardinal Wilton Gregory gave an invocation.

Biden and Harris (here with Emhoff) have said that getting the pandemic under control will be their administration's most pressing initial mission. Both have routinely met with health officials during the transition period, since they were elected in November.

Last Thursday, the Biden administration announced a $1.9 trillion pandemic relief proposal aimed at combatting the health crisis and the economic downturn it has caused since businesses began shutting down last March.

"We are ready to get this done," Biden said last week. "The very health of our nation is at stake."

The committee encouraged communities and individual Americans to participate in the memorial, asking U.S. officials nationwide to "light up city buildings" in light amber. The organizers told people around the country to light candles in their windows to mark what they called "a national moment of unity and remembrance."

Among those landmarks illuminated Tuesday night: "Urban Light," by artist Chris Burden, at the Los Angeles County Museum of Art.