All over the planet on Friday, millions of children and young adults walked out of their classrooms in an unprecedented collective action to demand a radical and urgent shift in society's energy and economic systems in order to avert the worst impacts of human-caused global warming and climate change.

With demonstrations in more than 100 countries and tens of thousands of schools, the worldwide Climate Strike is the largest since 16-year-old Greta Thunberg sparked a wave of increasingly huge marches and walkouts with her one-person strike outside the Swedish Parliament last year.



Since then, Thunberg has admonished and appealed to world leaders at COP24 and Davos, successfully securing a commitment from the European Union to fight the climate crisis while inspiring strikes all over the world. European students began holding weekly walkouts in Brussels in December, while Australian, and German young people are among those who have organized strikes as well.

"We have been born into this world and we have to live with this crisis, and our children and our grandchildren," Thunberg told a crowd of her peers in Stockholm in Friday. "We are facing the greatest existential crisis humanity has ever faced. And yet it has been ignored. You who have ignored it know who you are."

In Pictures:

On social media, supporters posted images and videos of students chanting, marching, and waving signs demanding action from their elected officials as well as rebuking some leaders who have criticized the students for skipping school. As one sign in London read, "I'll do my work when you do yours."

Uganda:

Brussels:

LOOK AT THE SIZE OF THE MARCH IN BRUSSELS!!! Young people are rising in 2052 places in 123 countries on every continents. There is no time to waste. We must #ActOnClimate. #climatestrike #klimaatstaking #FridayForFutures #GreenNewDeal @GretaThunberg via @JohnHyphen pic.twitter.com/3CGLMDYE8v — Mike Hudema (@MikeHudema) March 15, 2019

Minneapolis, Minnesota:

Sign in St. Paul Minnesota:

"If you don't act like adults, we will."#climatestrike #FridaysForFuture pic.twitter.com/xUMrJjGz0H SCROLL TO CONTINUE WITH CONTENT Never Miss a Beat. Get our best delivered to your inbox.





— Eric Holthaus (@EricHolthaus) March 15, 2019

Montreal:

Lisbon:

New York:

Beautiful scenes in NYC where thousands of students have gathered at Central Park for the #ClimateStrike. Huge cheers every time a new school joins in. pic.twitter.com/aDp2MujsRj — Lucky Tran (@luckytran) March 15, 2019

Kyiv, Ukraine:

In Kyiv, Ukraine, 100+ students appealed to Prime Minister Volodymyr Groisman and the govt to recognize climate change as one of the most pressing nationwide problems and to take appropriate action. #Climatestrike took place in six cities in Ukraine.

Photos: Olena Angelova pic.twitter.com/idIgr8rXvx — 350 dot org (@350) March 15, 2019

Barcelona:

HUGE! crowd out in #Barcelona as far as the eye can see. Young people are rising in 2052 places in 123 countries on every continents. There is no time to waste. We must #ActOnClimate. #climatestrike #klimaatstaking #FridayForFutures #GreenNewDeal @GretaThunberg @luckytran pic.twitter.com/IvzMZPwsBr — Mike Hudema (@MikeHudema) March 15, 2019

Santiago, Chile:

Nigeria:

Paris:

Bangladesh: