DENVER — Climate activist Greta Thunberg headlined an event at Denver's Civic Center Park on Friday. 

"This is real hope. This what we are seeing right now, this is the hope, the people," Thunberg said.

The Fridays For Future Denver Strike took place from 12 p.m - 2 p.m. on Friday at the Greek Amphitheater. The #FridaysForFuture movement was started by Thunberg, a 16-year-old Swedish activist.

"It should not be up to us to take the responsibility but since the leaders are behaving like children then we have no other choice," Thunberg said.

Last December, Thunberg shamed climate change negotiators in a speech in front of the United Nations Summit in Poland. She asked students to walk out of class on Fridays. Last May, 1.4 million kids around the world did just that.

RELATED: A Denver teen goes on strike for the climate every Friday — and this week, she will march with Greta Thunberg in NYC

They asked for adults to join them the next time around.

"How dare they leave this mess for their own children to clean up and solve," Thunberg said. "How dare they pretend that they are doing enough."

United Nations Climate Action Summit
Environmental activist Greta Thunberg, of Sweden, addresses the Climate Action Summit in the United Nations General Assembly, at U.N. headquarters, Monday, Sept. 23, 2019. (AP Photo/Jason DeCrow)

Thunberg's visit comes three weeks after the Global Climate Strike, which took place ahead of the UN Summit on Climate in New York. Protesters asked people to leave their jobs and take to the streets to demand action on climate change.

RELATED: Protesters in Denver take part in Global Climate Strike

Haven Coleman, a 13-year-old student in the Denver Public School District, is also a climate change activist. She's been going on strike every Friday since Jan. 4.

“Because it’s my future," she said. "Because it’s my generation's future. Because why wouldn’t you care about things? Like if it’s going to be hurting you or hurting the world, then you’re trash."  

She was invited to march with Thunberg in New York last month and also cofounded the U.S. Youth Climate Strike with two other teen activists. 

"Because we as young people are tired of constantly being betrayed by those who are supposed to work for our greater good," Thunberg said.

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