Tens of thousands of people celebrated Earth Day Saturday by taking to the streets in a historic day of action for science and truth. A massive March for Science took place in Washington, DC, and more than 600 sister marches took place in other cities around the world.


"We are marching today to remind people everywhere, our lawmakers especially, of the significance of science for our health and our prosperity," Bill Nye, honorary co-chair of the March for Science, told the crowd in DC.

Saturday's March for Science was the perfect launching pad to a week of action that will culminate in the Peoples Climate March in Washington, DC, on April 29. As Ploy Achakulwisut, PhD Candidate in Atmospheric Science at Harvard University, put it, "the Science March is about respecting science, the People's Climate March is about acting on it."

The week of action, dubbed "From Truth to Justice: Earth Day to May Day 2017," will feature more than 50 events, including the launch of visionary clean energy legislation, a speak-out of the 21 young people suing the U.S. government, massive youth convergence, direct actions and more.

"Scientists have not been eager to get politically involved, but in the face of unceasing attacks and organized denial, they're putting their credibility to good use," Bill McKibben, 350.org co-founder, said. "Now the rest of us can back them up next weekend when everyone gets to march!"

May Boeve, 350.org executive director, shared the same sentiment.

"The Peoples Climate March is the next step for the March for Science: a call to get more engaged in our political system, to confront power and to demand solutions," she said.

"The demands we will put forward—respect for Indigenous peoples, investments in communities on the front lines of the climate crisis, transitioning from fossil fuels to 100 percent clean energy economy that works for all, and more—highlight the intersections between our different struggles, and the common solutions we can work for together."

In addition to the march in DC this weekend, there will be hundreds of sister marches in cities across the globe.

Check out these amazing tweets from the March for Science: