Greta Jelen got her big idea on a day when high school students across the District walked out to join a protest over immigration policy.

She came away with a sense of power and community, she said, and was left feeling "not as alone as the election of 2016 had made me feel."

The now 16-year old junior at the School Without Walls said her experience in November sparked her idea to try to educate students about their civil rights and led to a three-day session in Washington that ended Thursday.

Gavin Grimm, the transgender student whose efforts to use the boys' bathroom at his Virginia high school led to a nationally followed legal battle, spoke.

A senior attorney with the American Civil Liberties Union talked about free speech and protests and the group's defense of the right of white nationalist protesters to rally.

Students acted out roles in staged interactions that might occur with police.

The speakers and sessions covered a wide swath: immigration, women's rights, voting rights, privacy rights, free speech and LGBTQ rights.

Jelen is a member of the ACLU club at her school and worked with the school and the ACLU of D.C. to set up her Washington D.C. Youth Civil Rights Summit.

When Jelen initially came up with the notion, she told her mother that "kids care, and I think that they'll come if we do this."

About 300 students from public and private schools in the city and Maryland registered.

Meg Grieve, a 16-year-old student at Washington Latin Public Charter School, said she was most looking forward to hearing from Grimm because he "has been through a lot, and will definitely . . . inspire us to keep fighting."

Grimm drew question after question and tried to help the students step into his place. "Try to imagine that if you had to center your days around finding a bathroom that you had access to . . . imagine what kinds of things you would be limited from doing," he said.

He told them about the nearly two-hour trips to the nearest clinic for transitional medical services, the insurance hurdles and the strain he said his transition put on his parents.

Grimm told a story about his first birthday after he came out when his twin brother didn't know he was transgender. His twin spent part of the party trying to figure out why the name of their turtle, which also happened to also be Gavin, was on the cake, Grimm said, which led to laughter from many of the students.

Students asked Grimm about how they could support their transgender friends, how he advocates for transgender rights, and how he deals with people using the wrong pronouns.

"We're always here for ambitious ideas that educate young folks about what their rights are and the work that we do," said Kendrick Holley, the community engagement manager for the ACLU of D.C., explaining why the organization helped make the event happen.

Students also heard from Claudia Quiñonez, who helped organize a group of undocumented students, parents and supporters into United We Dream, a reference to those who had gained legal status under the now eliminated Deferred Action for Childhood Arrivals. They watched a documentary on Joe Arpaio, the longtime Phoenix-area sheriff whose approach to jail and immigration issues attracted controversy, and a movie about Edward Snowden, the former NSA contractor who disclosed documents on government surveillance programs.

"Things that go on in our world . . . affect us, too, and I think it's really cool that we get to have those types of conversations," said Chloe Pine, a 15-year-old member of the ACLU club at the School Without Walls.

"More than most schools, since we live in D.C. we're very much surrounded by the political atmosphere that goes on in our world," Pine said. "We can literally walk down the street to the White House or to the Capitol and speak up for what we believe in."

Scott Michelman, senior staff attorney at ACLU of D.C., led a discussion with the students about their free-speech rights, and the students used that right to question the ACLU.

One student asked why the ACLU of Virginia defended the rights to rally of the white nationalists in Charlottesville.

Michelman told the students that it was "one of the toughest cases the ACLU has defended." He said that the court case the ACLU took part in was before the rally — and the violent and deadly exchanges it ignited — and was about the permit site.

"With any institution, the ACLU not being an exception, we should always be questioning, we should always be challenging what choices they make," Michelman said.

The discussion about free speech "emphasized how much I believe in free speech," said Grieve. "Everybody should have the right to say what they want to say."

During one session, students role-played about how they would act if a police officer tried to stop them and what to do if a situation became violent. Students evaluated how others reacted, telling them to keep their hands out of their pockets and not to wave their hands around.

The exercise, Holley said to the students, might help them stay out of jail and stay safe. "Your strength is not in fighting, it's in reporting," when interacting with the police, Holley said.

For Jelen, the three days reinforced her instinct that there was a community of students eager to learn more about their rights and activism.

"Sometimes people forget that D.C. isn't just the administration that's in the White House, it's the people that live there," Jelen said. "We can't help but get absorbed into the protests and the rallies and who's in the White House, but we're also our own people, and when we did that walkout and everyone came together . . . it was like everyone saw."

Jelen sees herself getting involved with public advocacy in the future. "This is definitely not something I know that's normal, that a lot of kids would take on, but it is for me."