Thousands of people showed up Saturday at New York's March for Science, including a retired high school teacher who warned that climate change, if ignored, will be America's "Armageddon."
New York joined cities around the world where activists marched to defend science from attacks including U.S. government budget cuts.
In Manhattan, scientists and supporters first gathered at a late morning rally near Columbus Circle at Central Park West.
Participants, including some wearing lab coats, then walked down Broadway to midtown Manhattan, close to Times Square. Broadway was closed to traffic between Times Square and Union Square.
Marchers said they're worried about political involvement in science that rejects, for instance, climate change, environmental concerns and the safety of vaccines. Activists pointed to the immigration policies of the Trump administration they say could keep some valuable foreign scientists from working in the United States.
At the site of the rally near the Trump International Hotel & Tower, two words were heard shouted above the crowd: "Dump Trump."
Barbara Wasilausky, a retired high school science teacher and registered nurse from Long Island, warned that "climate change is what is going to be our Armageddon if we don't do something about it." And instead of seeking facts that can be proved, she added, "we've been too quick to just click on stories, not read them, not think about them, and make our decisions that way."
Nearby, a small girl in a stroller held up a sign that read, "The oceans are rising and so are we." And another woman's sign said, "Make America think again."
Other cities staging marches include Washington, Berlin, London and Sidney, plus hundreds of smaller communities.
The marches on behalf of science were part of global Earth Day.