Around the world, the Sept. 20 Climate Strike saw millions take to the streets with homemade signs, chants, and speeches to spread a message to world leaders—do more to fight climate change, and do it faster.

“From shifting weather patterns that threaten food production, to rising sea levels that increase the risk of catastrophic flooding, the impacts of climate change are global in scope and unprecedented in scale,” according to a recent from by the United Nations. “Without drastic action today, adapting to these impacts in the future will be more difficult and costly.”

In Boston, about 7,000 protestors heard from Gina McCarthy, a former member of the Environmental Protection Agency, Mayor Martin Walsh, and Hartman Deetz, a member of the Mashpee-Wampanog tribe.

“We cannot afford to lose because this is not a matter of who is rich or who is poor. It’s a matter of who’s alive and who’s not,” Deetz said in his speech.

Several Brimmer and May students also attended the Boston event.

“It was really inspiring to be around so many other people who feel as passionately about climate and social justice as I do, and it was inspiring to hear people talking about the stories they had to tell,” Anja Westhues ’20 said.

According to Vox, 40,000 attended the protest in France, 2,600 in Ukraine, 5,000 in South Africa, 10,000 in Turkey, 5,000 in Japan, 100,000 in London, 330,000 in Australia,  250,000 in Manhattan, and 1.4 million in Germany.

Around the globe, notable speakers included Alessandro Dal Bon, a 15-year-old organizer from New York, Bill McKibben, an award-wining environmentalist and author, and Cynthia Leung, another young activist from Manhattan.

Greta Thunberg, 16, who spoke at the recent Climate Summit in front of several world leaders at the United Nations in New York, also led the strike.

“This is all wrong,” Thunberg said in front of the United Nations. “I shouldn’t be up here. I should be back in school on the other side of the ocean. Yet you all come to us young people for hope. How dare you. You have stolen my dreams and my childhood with your empty words. Yet I am one of the lucky ones. People are suffering. People are dying.”

After her remarks, Trump retweeted a video clip of her speech, appearing to mock the young activist: “She seems like a very happy young girl looking forward to a bright and wonderful future. So nice to see!”