In one of the largest environmental protests in history, students from around the world walked out of their schools and flooded the streets on September 20 to protest government and business inaction on climate change. Expressing themselves through promotional products, they shared their unified message of preserving the environment.

Inspired by Greta Thunberg, the 16-year-old Swedish climate activist who began weekly protests last year, young people in over 150 countries are demanding an end to the age of fossil fuels, corporate pollution and environmental destruction. During the Global Climate Strike, Thunberg was slated to lead a demonstration in New York City, in which the 1.1 million students in the city’s public schools were excused to join the march, The New York Times reported. Similar rallies took place in Washington D.C., Los Angeles, Boston, Seattle and other major cities.

In Philadelphia, thousands of children, their parents and even grandparents gathered at City Hall to voice their grievances. Many brought creative, colorful and thought-provoking homemade banners and signs, urging government officials to pass the Green New Deal – proposed legislation that would mobilize public resources to tackle climate change and transition to an economy that uses 100% renewable energy by 2030. “It makes me feel really empowered to see that thousands of people here and across the globe are taking this seriously,” said Mayana Ashley-Carner, a high school student and volunteer at youth-led activist group Sunrise Movement. “This is the community that’s going to change the world.”

The saints come marching in! Philly #ClimateStrike pic.twitter.com/5N3o5GD034

— John Corrigan (@Notready4Radio) September 20, 2019

Several activist organizations were on hand, all decked out in branded T-shirts. The Earth Quaker Action Team designated “marshals” wearing neon green vests to coordinate the ever-growing crowd. Another organization – Socialist Alternative – sold political and social justice-themed buttons that were designed by its various members across the United States. “We want people to be empowered with building the next steps beyond this,” said organizer Jed Laucharoen. “Little individual changes like using a paper straw is not going to get this done. We need to talk about changing the system, getting rid of the for-profit motive and taking big energy companies and manufacturers into democratic public ownership.”

Defend Our Future, another activist group, stirred up excitement by handing out free branded T-shirts. “We make people feel they’re part of the group and we also pique their curiosity about who we are and what we’re about,” said Ben Schneider, the organization’s communications leader. “We want to do more events like this to engage more young people and make them feel they have the resources they need to affect climate change.”

The Global Climate Strike comes three days before the United Nations’ 2019 Climate Action Summit in New York City, where countries are expected to present their strategies for reducing greenhouse gas emissions under the 2015 Paris climate agreement, Vox reported. A second worldwide strike is planned for September 27.