Carrying signs calling for “Alternative energy, not alternative facts” and to “Make America smart again,” more than 30,000 marchers packed Broadway in support of science Saturday.

The March for Science in New York was one of more than 600 such demonstrations worldwide, including one in Washington, DC that drew Bill Nye the Science Guy.

The events, billed as a nonpartisan “celebration of science” for Earth Day, took a political tone.

“I want to show people that we can’t pretend science isn’t real because of ulterior political purposes,” said Aynna Lewis, 30, a Long Island doctor.

President Trump issued a statement saying: “We should remember that rigorous science depends not on ideology, but on a spirit of honest inquiry.”

Marcher Jeffrey Shyn of Boston said: “I’m a physician, but I feel like the march today goes beyond politics. It’s about how we come to understand what truths are. That’s what science aims to discover.”