Marchers will gather at 9 a.m. at Pershing Square Park in downtown Los Angeles, on, appropriately enough, Earth Day.

“The incredible diversity of those supporting this march has been inspirational,” said lead organizer Alex Bradley. “We’re all uniting in our passionate support of science and its integral role in informing policy and benefiting public and environmental health.”

Organizers will host a science expo at Pershing Square Park from 9-4 featuring informational booths, science demonstrations for children, trainings, teach-ins, and other activities.