Hillary Clinton spoke about finally breaking the "glass ceiling" to elect a female president. Joe Biden was scheduled to be the final speaker in Chicago on Monday night, even as protesters against the war in Gaza churned a few blocks from the convention hall.

Here are some takeaways from the first night of the convention.

A surprise Harris appearance to pay tribute to Biden

The vice president made an unscheduled appearance onstage to pay tribute to Biden ahead of his own address to the convention. She told the president, "Thank you for your historic leadership, for your lifetime of service to our nation, and for all you'll continue to do."

On a night meant to honor the president who stepped aside to make way for Harris, the vice president added, "We are forever grateful to you." Her running mate, Minnesota Gov. Tim Walz, and her husband, Doug Emhoff, were in the stands to cheer her message.

Harris, in her brief remarks, said that looking out on the crowd, "I see the beauty of our great nation," stressing the importance of promoting diversity and embracing optimism.

Hillary Clinton revives talk of breaking that 'glass ceiling'

Clinton was greeted with wild and sustained applause that lasted for more than two minutes before she quieted the crowd. She delivered a fiery speech hoping that Harris could do what she could not -- become the first woman president by beating Trump.

Clinton evoked her 2016 concession speech by referencing all the "cracks in the glass ceiling" that she and her voters had achieved. And she painted a vision of Harris "on the other side of that glass ceiling" taking the oath of office as president.

She closed her speech with a striking desire for someone who's stood at the pinnacle of American politics and power: "I want my grandchildren and their grandchildren to know I was here at this moment. That we were here and that we were with Kamala Harris every step of the way."

Clinton dipped into traditional political attacks in her speech, including mocking Trump's criminal record. That led to chants of "lock him up" -- mirroring the ones that Trump's supporters directed at Clinton in 2016.

Tracing a line from Jesse Jackson to Kamala Harris

An early theme of the evening was celebrating the Rev. Jesse Jackson, a longtime civil rights leader in Chicago and former presidential candidate in 1984 and 1988. Many Democrats credit him with blazing a trail that helped Barack Obama win the White House in 2008 and Kamala Harris become the first woman of color nominated for the presidency.

Jackson was saluted from the stage by several speakers, including Chicago Mayor Brandon Johnson and California Rep. Maxine Waters. There was a video montage of Jackson's career and legacy that played before the 82-year-old Jackson himself came to the stage in a wheelchair, thrusting his arms skyward and grinning. Jackson has been diagnosed with Parkinson's disease.

During the 1984 Democratic convention in San Francisco, Jackson gave a speech declaring that America is "like a quilt: Many patches, many pieces, many colors, many sizes, all woven and held together by a common thread." The address became known as the "Rainbow Coalition" speech, and Jackson used momentum from it to seek the Democratic nomination again in 1988.

Harris has called Jackson "one of America's greatest patriots."

Remember COVID? Democrats don't want voters -- or Trump -- to forget

Democrats opted to shine the convention spotlight on the harrowing subject of the coronavirus pandemic.

It was a reflection of Democratic frustration at how Trump has portrayed his tenure in office as a golden age for the country, even though hundreds of thousands of Americans died of COVID-19 during the last year of his term.

There are plenty of risks for Democrats in hammering the pandemic. Even more people died of the virus during Biden's presidency than during Trump's, voters have shown an eagerness to move on and some preventative measures championed by Democrats -- like school closures and masking -- are not popular in retrospect.

Still, the lineup of early speakers focused on Trump's performance during the pandemic. Minnesota Lt. Gov. Peggy Flanagan recalled how her brother was the second person in Tennessee to die of the disease and how she couldn't visit him or hold a memorial service. Rep. Lauren Underwood of Illinois, a nurse, said of Trump: "He took the COVID crisis and turned it into a catastrophe. We can never ever let him be our president again."

Rep. Robert Garcia, whose mother and stepfather died of the disease in 2020, recalled Trump's missteps and concluded with one of the slogans of Harris' young campaign: "We are not going back."

Democrats one-up Republicans on labor

Trump's convention last month featured a rare appearance from a union leader at such a GOP event: Teamsters President Sean O'Brien. That's reflective of how Trump's populism has cut into Democrats' advantage with union households.

In that speech, O'Brien did not endorse Trump. But he criticized both major political parties for not doing enough to help working people.

Democrats didn't invite O'Brien to their convention, but they countered with a half-dozen other union leaders onstage Monday. And then Shawn Fain, head of the United Auto Workers, led a blistering chant of "Trump's a scab!" while wearing a red T-shirt emblazoned with those words.

Fain noted that Biden visited a UAW picket line last year and, when autoworkers struck in 2019, Harris, not Trump, walked the picket lines. "Donald Trump is all talk and Kamala Harris walks the walk," Fain said.