The second annual March for Science was held on the National Mall in Washington Saturday and more than 200 similar events were held around the world.
Thousands of people attended the flagship event in Washington, but the turnout was notably smaller than last year.
Saturday's march took place after a turbulent year in science policy under the Trump administration. Science-related changes from the White House have included the withdrawal of the U.S. from the global Paris Agreement on climate change and the president's championing of coal-fired power plants. Washington is also seeking to roll back environmental regulations.
One of the demonstrators carried a sign that said "Make America Smart Again" -- a play on the president's campaign slogan of "Make America Great Again."
"Science is what separates facts from fallacies, falsehoods and fanaticism," David Titley, a retired rear admiral told the crowd in Washington. Titley who led the U.S. Navy's task force on climate change said, "If we ignore and denigrate science we do so at our own peril."
But march organizers say the attacks on science did not start with the Trump administration. For decades, they say ideology has overtaken evidence on issues in women's health, gun violence and other controversial subjects.
"This isn't a new phenomenon," March for Science Interim Executive Director Caroline Weinberg said recently. "We reached a tipping point. But these protests should have been happening for years."
In a polarized country, however, the march walks a fine line.
This year, March for Science organizers rallied support to lift a ban on gun violence research.
Weinberg said they debated whether the issue was too partisan for the group to weigh in on.
But they decided that it was more important to support research that would help policymakers make good decisions.
"It's only partisan because we've let that become the conversation," she said. "Pushing against that, I think, is one of the most vital roles we can play."