A protestor holds a sign in support of science during the March For Science in Seattle, Washington, US April 22, 2017. [Photo/Agencies]

NEW YORK - Tens of thousands of people, mostly scientists, students and research advocates, took to the streets in New York and Chicago, Saturday to promote the understanding of science and defend it from being compromised by proposed federal budget cuts.

The March for Science, coinciding with Earth Day, began with a rally at 10:30 am Saturday near Columbus Circle at Central Park West. An estimated number of over 30,000 people filled up at least a dozen blocks north of the Trump International Hotel at noon.

Marchers held signs with slogans: "Science should be shared not censored," "Rise up before the waters do," "Dinosaurs didn't believe in climate change either," "stop the war on facts," "Denial is not a policy," and "we're not just resistors, we are transformers," etc.

As the massive crowd walked down to Broadway to midtown Manhattan, chants of "Science makes America great" rippled down the street. The march was set to end at West 52nd Street. A 1.6-mile stretch of Broadway was closed to cars for the march.

More than ten thousand people took to streets in Chicago on Saturday to join the worldwide event of "March for Science."

People held placards and banners reading "Don't have a planet B," "Climate change is real," "Science, not silence," "We love science," "Science, our future," "Fund research," "Planet Earth is all we have, save it," "Without science, it's just fiction," "Evidence over ignorance."

A five-year-old boy won praise for the placard he held, which read "Fund science, fund my future."

A lot of people joining the march are university students and teachers, or work at research institutions, some of them are even in their lab robes, or wear a shirt with arithmetic formula.

The march started near Congress Parkway, a main driveway in downtown Chicago and ended in the Field Museum, a museum of science and industry on Lake Michigan.