Launched from the tears and frustration of angry Marjory Stoneman Douglas High School students, more than a million people are expected to participate Saturday in March for our Lives gun-control rallies around the world.

Billed as a long overdue conversation about gun violence, the main event will take place in Washington, D.C., where local officials are bracing for the possibility of 500,000 people – many of them under the age of 18 and led by Douglas High student activists – marching down Pennsylvania Avenue to rally near the Capitol.

At the same time, more than 800 so-called “sibling marches” will take place in communities around the United States — from San Francisco to York, Pa., from Birmingham, Ala., to Parkland, home of the high school where a gunman killed 14 students and three staff members on Feb. 14.

With other marches taking place that day around the world, including London, Madrid, Paris, Tokyo and Seoul, student organizers have said they expect the total number of participants to top 1 million.

“It just shows that the youth are tired of being the generation where we’re locked in closets and waiting for police to come in case of a shooter,” said Alex Wind, a junior at Douglas High.

“We’re sick and tired of having to live with this normalcy of turning on the news and watching a mass shooting,” he said.

In Palm Beach County, marches will be held in Boca Raton, Delray Beach, Jupiter and West Palm Beach, where nearly 2,000 participants are expected to meet at Dreher Park and attempt to march along Southern Boulevard toward Mar-a-Lago in Palm Beach, where President Donald J. Trump will be staying this weekend. But the marchers will not cross the bridge and instead gather by the seawall along Flagler Drive just south of Southern Boulevard.

In addition, seniors in Boynton Beach will also hold demonstrations in support of the marches.

But many South Florida students, including several from Palm Beach County and from Douglas High School, are traveling to Washington for Saturday’s main event, where the forecast calls for a high of 46 degrees.

“I hope it gets a lot of people energized and motivated to make changes because that could have a profound impact on our legislation in the future,’’ said Adin Segal, a senior at William T. Dwyer High School in Palm Beach Gardens, who is attending the D.C. march with his parents.

The demonstration is being organized by Never Again MSD, a group of students who survived the Feb. 14 shooting. Everytown for Gun Safety, a gun control advocacy group, is helping the students plan and coordinate the event.

The march, which took root just hours after the shooting when Douglas High survivors got together to brainstorm a prevention plan, is not a protest against Trump or any individual lawmaker.

“In the tragic wake of the seventeen lives brutally cut short in Florida, politicians are telling us that now is not the time to talk about guns. March For Our Lives believes the time is now,” according to the Never Again MSD mission statement.

“The mission and focus of March For Our Lives is to demand that a comprehensive and effective bill be immediately brought before Congress to address these gun issues.”

The rally is being paid for by donations to a March for Our Lives Action Fund and to a GoFundMe campaign that has raised more than $3.3 million. Contributions have come from a number of celebrities, including George Clooney, who is expected to attend, Steven Spielberg and Oprah Winfrey – each of whom has chipped in $500,000.

Musical performances by singers such as Ariana Grande (whose concert last year at Britain’s Manchester Arena was the site of a terrorist attack), Jennifer Hudson and Miley Cyrus, will be broadcast on 20 Jumbotrons along Pennsylvania Avenue.

On Tuesday, talk show host Jimmy Fallon promoted the march during his "Tonight Show" monologue.

“I just want to remind everybody that this Saturday, March 24, students from Marjory Stoneman Douglas High School have organized a march in Washington,” Fallon said. “It’s called the March for Our Lives, and it’s to tell the government, loud and clear, that we demand change on the issue of gun control.”

The march has gotten so big, it has upstaged one of the district's biggest events: the annual National Cherry Blossom Festival. Its opening ceremony has been moved to Sunday to alleviate congestion.

"As the young men and women from Parkland, Florida, have been preparing for Saturday's event, the District has been preparing to keep them safe here in Washington," D.C. Mayor Muriel E. Bowser said earlier this week. "We are very much looking forward to supporting this rally."

Federal agents and D.C. police will be in full force to ensure the safety of protesters. Metro lines will run every two or three minutes, 2,000 portable toilets will be provided and medical tents will double as reunification points in case participants get separated from loved ones.

"We are looking forward to these teenagers and everybody who believes that we must do more to have sensible gun regulation in our nation and to keep children safe in their schools and in their neighborhoods,'' said Bowser, who appeared with singer Justin Timberlake a few days ago in a promotional video for the march.

Many people in the D.C. area are offering to help visiting students by offering beds, food and transportation.

“We wanted to do something to help,’’ said Gabrielle Zwi, one of four students at Walter Johnson High School in Bethesda, Md., who launched an online housing network seeking families willing to open their homes to students.

Within days, the network found more than 200 residents who offered beds, couches or rooms at their homes to more than 300 students.

“Our whole group was completely shocked by the response that we got. I think it’s absolutely wonderful,’’ Zwi said.

Zwi’s high school is hosting a free pot luck dinner for visiting students Friday night. Families who are unable to host students have offered to make bag lunches or donate subway cards.

The main Douglas High activists, who appeared on 60 Minutes last Sunday, left South Florida over the weekend to promote the D.C. march with a media blitz in New York.

On Monday, they held a live discussion, viewed by more than 700,000 people, at Twitter's New York headquarters using the hashtag #AskMSDstudents. On Tuesday, they participated in a forum at Harvard University.

Earlier Tuesday, Douglas High students held a pep rally in Parkland to kick off the March for our Lives.

“Let us do what our politicians did not do when our school was transformed into a battleground,’’ said Demitri Hoth, a Douglas High senior. “Let us fight for justice. Let us extend our hand to every student, teacher, parent to come together to demand that our government do something. Because enough is enough.”


Palm Beach County marches Saturday

Boca Raton: 10:30 a.m. from Boca Raton City Hall, at 201 W. Palmetto Park Road, to the Mizner Park Amphitheater

West Palm Beach: 2 p.m. from Dreher Park, at 1100 Southern Blvd, to as close to Mar-a-Lago as security allows.

Delray Beach: 4 p.m. from Old School Square, at 51 N Swinton Ave., to the beach.

Jupiter: Noon from Jupiter Community Center, at 200 Military Trail.

Other marches of note

Boynton Beach: Several senior communities will be rallying Saturday. On Military Trail, from Boynton Beach Boulevard to Lake Ida Road, grandparents plan to rally for a ban on assault weapons. In addition, Cascades, a community on Military Trail south of Golf Road, will hold rallies at noon.

Parkland: 10 a.m. at Pine Trails Park, 10555 Trails End

Stuart: 10 a.m. at the bandshell at Memorial Park, 300 S.E. Ocean Blvd.

Port St. Lucie: 4 p.m. at Tradition Square