At a rally full of scientists,underground video sex site things were bound to get a bit geeky.

On Sunday, thousands of scientists and supporters gathered in Boston's Copley Square to "stand up for science" under the Trump administration.

Their signs were, predictably, quite clever.

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Many rally-goers were in Boston for the annual meeting of the American Association for the Advancement of Science (AAAS), the world's largest general scientific society.

"You don't usually see these kinds of rallies and demonstrations at scientific meetings," Kishore Hari, a chemist-turned-science educator, said ahead of Sunday's rally.

"It's a sign that scientists are feeling not just under attack, but like the integrity of their work is in question," he said.

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Scientists at the rally voiced concerns about what they say is President Donald Trump's "anti-science" administration.

Trump has tapped cabinet officials who deny the mainstream scientific consensus that climate change is happening, and that human activity is largely to blame. The newly confirmed head of the Environmental Protection Administration, Scott Pruitt, called himself the "leading advocate against the EPA" during his tenure as Oklahoma's attorney general.

Since taking office, Trump has also moved to curb the flow of information from key government agencies involved in environmental issues. Along with the EPA, the departments of Interior and Agriculture were ordered to stop sharing information with the public, including through social media accounts.

In response to the Trump administration's actions, U.S. scientists have taken the relatively rare step of banding together.

Last December, a few hundred scientists held a rally outside the annual fall meeting of the American Geophysical Union. That event -- plus the widespread Women's Marches in January -- have inspired the larger March for Science, a demonstration planned for Earth Day on April 22.

"Scientists usually like to be in their labs or their offices, just doing their thing, and rarely do they come together to fight for something," said Astrid Caldas, a climate scientist for the Union of Concerned Scientists, a science advocacy organization.

Caldas noted that rallies aren't the only way scientists can speak out. Some people may feel more comfortable engaging directly with policymakers, penning articles, or working behind the scenes.

"I think it's important that every scientist's voice is heard," she said. "There are many ways of advocating for science."

Hari, the science educator, said he is organizing more than 260 satellite events to coincide with the main March for Science in Washington this spring.

"Usually you hear the phrase 'let the science do the talking,'" he said. "I don't think that's going to be the case any more."