In a large House caucus room, Rep. Jason Crow, D-Colo. -- a decorated Iraq and Afghanistan War veteran who helped barricade the House chamber on Jan. 6 and defend the lives of his colleagues -- led members in sharing their reflections on the insurrection.

Rep. Dan Kildee, D-Mich., argued the importance of agreeing about the truth of that day and pulled out a piece of glass he said he picked up from a broken window in the Capitol in the aftermath of Jan. 6 that he carries in his pocket each day.

"Truth is clear as this shard of broken glass that I have carried with me the last 365 days… as a reminder -- a constant reminder -- in my pocket of the brutality of that day," he said. "Only truth and accountability will give us the opportunity to find a path toward reconciliation. Only truth will begin to thaw the bitterness that characterizes our current divisions."

Rep. Val Demings, D-Fla., who is running against Republican Sen. Marco Rubio for Senate, called out lawmakers who have whitewashed the day and "forgotten their oath," she said, "overshadowed by their quest for power and their pathetic fear of election officials counting every vote."

"Many people call themselves patriots. But true patriots don't lie. They don't steal. They don't cheat," she said, taking the chance to thank law enforcement officers as the former police chief in Orlando. "But out of the ashes, good things can rise."

In a panel discussion moderated by Librarian of Congress Dr. Carla Hayden, historians John Meacham and Doris Kearns Goodwin addressed the significance of the anniversary of the attack and the importance of sharing a common truth about the events of the day instead of whitewashing what happened.

"This is about our future and all of us have a responsibility to remember that a more perfect union is about we the people, not a singular person," Meacham said.

He echoed Biden in calling the moment Americans face now "an inflection point" and said the founders would “want us to defend their experiment."

"In my lifetime this is the hardest moment for democracy," Goodwin added. "We have to recognize how deep that challenge is and not to sugar coat it, as Lincoln would say... but I think it can come back again."

The panel got some help at the top from the cast of the Broadway hit "Hamilton" -- which explores the foundations of American democracy and George Washington's choice to surrender power after two terms.

"You're all stewards of the American experiment," creator Lin-Manuel Miranda said in a pre-recorded video, before the cast sang, via Zoom, the song "Dear Theodosia" from the musical.

-ABC News Benjamin Siegel

Former Republican Vice President Dick Cheney departed the House chamber after the moment of silence walking alongside his daughter, and told ABC News, "Very proud of Liz," when asked for some parting thoughts.

The somewhat frail former vice president -- clad in crisp navy pinstripe suit -- was greeted by a swarm of reporters and still photographers as he became the unwitting star of this unusual day on Capitol Hill.

"It’s great coming back," he said. "Liz is doing a hell of a job. I’m here to support her."

When asked for his reaction to Republican leadership’s handling of the day, Cheney -- not one to mince words -- said, "Well, it’s not a leadership that resembles any of the folks that I knew when I was here for 10 years -- dramatically."

Rep. Liz Cheney, R-Wyo., who holds the seat her father once held, said GOP leadership is "very concerning," adding, "I think a party that is in thrall to a cult personality is a party that is dangerous to the country, and I think we clearly have got to get to a place we are we are focused on substance and on issues."

The former vice president took the long walk across the Capitol toward the Senate chamber, stopping momentarily to take in his own white stone bust outside the office of Republican Leader Mitch McConnell, who is far from the Capitol, and instead, at a funeral for a late GOP senator in Atlanta.

-ABC News' Trish Turner, Mariam Khan and Benjamin Siegel

One year ago at this hour, a mob of Trump supporters moved toward the Capitol after a speech from the former president at the Ellipse.

"If you don't fight like hell, you're not going to have a country anymore," he said then, stoking anger in the fired-up crowd, telling them he would march with them to the Capitol to stop Congress from certifying Biden's electoral vote win.

"Now, it is up to Congress to confront this egregious assault on our democracy. And after this, we're going to walk down, and I'll be there with you," he told them.

The temporary fencing that ringed the Capitol for more than six months after, and again briefly for a September demonstration has not returned for the dark anniversary, though that could change quickly if conditions warrant, Capitol Police Chief Tom Manger told ABC News Chief Justice Correspondent Pierre Thomas in a recent interview.

Thursday's ceremonies are scheduled to conclude in the evening with a prayer vigil on the Capitol center steps. Members of the House and Senate were invited to observe the anniversary with prayer and music.