Along with seas of pink "pussyhats," the Women's March on Saturday that attracted hundreds of thousands of women worldwide was marked by signs.
There were funny signs—"Now you've pissed off grandma." There were inspirational signs proclaiming, "I can be president!" that little girls carried. There were profanity-laden signs and those poking fun at newly-inaugurated U.S. President Donald Trump. "We shall overcomb," was a popular one.
At the end of the marches, many of those signs were laid at prominent landmarks, like the White House gate and outside Trump hotels the world over. Others, meanwhile, were stuffed into overflowing trash cans. But there are some folks who are desperate to save the placards from the trash: Museums are collecting them to be preserved as historical artifacts.
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"We knew [the march] was a very important moment in London protest history, so we were very keen to make sure it was recorded," Stef Dickers, special collections and archives manager at the Bishopsgate Institute, a cultural institute in London, told Fortune. "History doesn't end in 1945. History is made every day."
He and digital archives manager Nicky Hilton tweeted on Saturday that Bishopsgate was collecting items from the Women's March in London, that attracted an estimated 100,000 people to the city's Trafalgar Square.
Other institutions like the Smithsonian's National Museum of American History and the Newberry Library in Chicago also sent out tweets about collecting signs from the march.
Dickers says Bishopsgate tries to save items from every London demonstration it can. Its archives feature artifacts from the two largest demonstrations in British history—the 1866 Reform League protest in Hyde Park that drew an estimated 200,000 people and the 2003 protest against the Iraq war that attracted an estimated 2 million.
But Bishopsgate was especially interested in preserving items from the Women's March because of the protest's grassroots nature. Unlike so many demonstrations, Saturday's march wasn't about one political party or a single subject matter. Instead, participants marched based on their own interpretation of recent events; some opposed Trump specifically, while others had broader concerns about feminism, women's rights, and the rights of people in the LGBTQ community.
"We were partly excited because people were telling their own story," Dickers says. "They w ent to this for their own reasons."
The worldwide nature of the march was also an important factor. "The solidarity shown across the world, in various cities, brought an extra dimension to [the march]." Dickers says.
In addition to signs and t-shirts, Bishopsgate is collecting photos and videos from participants of the march so it has a "bottom-up" record of the Saturday's events, rather than one that's "top-down."
Eventually Bishopsgate will make the items it collects available to the public—either on site or online. So far, there's been a slow trickle of donations, Dickers says, but there's a sense of urgency to the effort.
"We need to do this quickly," he says. Otherwise, "very soon, this history gets lost."