They didn’t have a plan at first. Five friends determined to join protests over the police killing of George Floyd arrived in downtown Washington on Saturday with one goal: Get to the White House.

As they walked south toward the bright white pillars in the distance, the group began to call out to passersby — people out for walks or jogs, some curiously eyeing the young people brandishing signs and face masks, marching with their fists held high.

“Walk with us,” called Jasmine Grobes, 27. “Come on! Walk with us.”

By the time they reached the metal barricades around Lafayette Square, that group of five had swelled to nearly 50 times that number. Many returned the next day. More arrived the next and the day after that.

Although the issues at the core of these protests are not new, experts said, the diversity of the crowd and the sustained momentum are. Several longtime protesters have wondered: Why now? Experts cite a confluence of factors, including a mainstreaming of protests, a backlash to citywide vandalism, the response to a fortified Washington, frustration with the government’s response to the coronavirus pandemic and a growing recognition of unequal treatment of black people.

After peaceful protesters were forced from Lafayette Square — often referred to as “the people’s park” — by federal officers wielding gas and pepper bullets before President Trump’s Monday photo op at St. John’s Episcopal Church, the number of demonstrators ballooned.

Each night, departing protesters have called out to police, “see you tomorrow.”

By Wednesday, thousands had gathered downtown. The crowd was made up of families, couples, retirees, teenagers, stay-at-home moms, professionals and military veterans. They marched until almost 3 a.m.

Rashawn Ray, a sociology professor at the University of Maryland and a fellow at the Brookings Institution, said if momentum continues, the demonstrations could mark a turning point in the larger movement against systemic racism that would mirror shifts from the civil rights movement in the late 1960s.

“The speed at which the movement for black lives has been able to diversify what the protest crowd looks like speaks, on one hand, to the fact that maybe there are a lot of people who want to see racial equality and want to see our country live up to its highest potential,” he said. “On the other hand, it also speaks to the ways the world around that movement has changed.”

For several years, the Black Lives Matter movement and organization has led protests and digital awareness campaigns in response to the killing of black men and women around the country, beginning around the death of 17-year-old Trayvon Martin in 2012.

While many of the names of the dead have become nationally recognized — Michael Brown, Tamir Rice, Sandra Bland, Philando Castile and others — for years, large-scale protests associated with the movement failed to gain sustained traction in white circles.

Then the 2016 election happened, and a new era of protesting began.

The day after Trump was inaugurated, hundreds of thousands of women gathered in Washington to voice their opposition. Many marched for the first time, and some haven’t stopped.

In the years Trump has held office, protests in the District and around the country have increased in frequency and size. The National Park Service estimates more than 700 permitted protests descend on the nation’s capital each year.

The issues vary widely. So, too, have the types of participants.

Youth-led protest movements, such as the worldwide push to decrease global carbon emissions to slow climate change, have trained participants in civil disobedience. Dana R. Fisher, a University of Maryland sociology professor who studies protest movements and routinely surveys participants, said more people than ever are using disruptive tactics — including being arrested, holding sit-ins and blocking traffic.

All the while, Black Lives Matter community organizers have continued to shine a light on police use of force and the criminal justice system’s impact on black communities. They have partnered with other organizations to sponsor marches and champion causes such as women’s rights or the humane treatment of immigrants.

“The intersectional issues that people care about is coming to bear,” Ray said. “Young people today have friends who are black and friends who are gay and friends who are trans, and they are seeing in real time how these friends are treated differently in society or could be in danger.”

The video of Floyd’s final moments showed him pinned to the ground for more than eight minutes as onlookers pleaded with police. Floyd cried out for his mother. Then, he went limp.

Ray said the power of seeing “a dead body on the ground” may have mobilized masses who have held recent protests in cities from Washington to Salt Lake City.

“Almost everyone in America saw that video, in a way that was very similar to how Americans in the 1950s all saw Emmett Till’s body in a casket after he was lynched,” Ray said. “They watched George Floyd’s body under the knee of that police officer while he called out for his mama, who has been dead for two years. That does something to people mentally, emotionally.”

When Attorney General William P. Barr personally ordered law enforcement to remove protesters near the White House this week, millions of Americans watched as officers launched riot-control munitions at peaceful demonstrators before the president strolled through an empty Lafayette Square.

Until that moment, people such as Leslie Calamese, 50, had not considered joining the protests outside the White House — they seemed too violent, too big. Too much gas directed at protesters, too much uncertainty.

But after watching from her home in Woodbridge, Calamese changed her mind.

On Tuesday, she stood with her three children — Kacy, 12; Kamryn, 14; and Kennedy, 17 — explaining what to do if the peaceful atmosphere turned.

“We felt helpless just sitting home, watching what happened out here,” Calamese said. “We’ll leave well before curfew, but I thought it was important for them to experience this.”

It was the girls’ first protest.

“I was nervous at first,” Kennedy said. “But I’m glad we came.”

Calamese, who spent much of the day on edge watching police for any sign of escalation, said she was shocked by the diversity of the crowd.

“This generation is different than past generations,” Kennedy said. “It was a whole melting pot, and it was really inspiring because everyone is starting to see how this is not okay.”

Several demonstrators said they wanted to show the government and the media, which had replayed images of vandals setting fires and shattering storefronts, that the protests were overwhelmingly peaceful and most wanted no part in violence.

By Tuesday, the group had self-patrolled. Protesters who stepped out of line to toss water bottles at police or shake the tall fence erected around Lafayette Square were shouted down by chants of “peaceful protest.”

One man, who ripped the 16th Street NW street sign from the top of a lamp post, was booed by the crowd and carried off by protesters who yelled, “get out of here” and “don’t give [police] a reason!”

Grobes and Aaron Covington, 26, whose group of friends has coalesced into a nascent organization, have found a rhythm. Every day, the group leads a march through Washington.

They stop every nine blocks for nine minutes — a nod to the nearly nine minutes the Minneapolis officer knelt on Floyd’s neck — as some at the front take turns giving speeches or leading chants through a megaphone.

Organizers said a hallmark of these marches is the way the crowd grows as it moves — with people joining in from their homes or pausing on their way to work to cheer them on. One woman exiting a supermarket loaded her bags in a car before bringing her children to join the procession, Covington said.

By Tuesday, he had begun to go hoarse.

As the crowd turned up the historical U Street NW corridor, he looked around and spotted a white man nearby exuberantly chanting “black lives matter.” He held out the megaphone.

“You want it?” Covington said. “Go ahead, take it.”

The man held the speaker to his lips and continued the drum beat.

“Black lives matter,” he chanted.

“Black lives matter,” the crowd called back.

Covington and his friends stood back, watching the scene. At first, he said, he was struck by the newness of it, a white man leading a crowd of many colors down a street in the District calling for the equal treatment of black people.

“Then I thought, you know what? I’m tired. I’m tired of marching. I need a break,” he said. “This is our struggle, yes. It’s something we own, but it’s not something we bought. It’s about time other kinds of people step up and help us carry this.”