On the first full day of Donald Trump’s presidency, hundreds of thousands of people crowd into the U.S. capital for the Women’s March on Washington, a massive protest in the nation’s capital aimed largely at the Trump administration and the threat it represented to reproductive, civil and human rights.

At the same time, more than 3 million people in cities across the country and around the world held their own simultaneous protests in a global show of support for the resistance movement. It was the largest single-day protest in U.S. history.

During the 2016 presidential campaign, the release of a 2005 recording of Trump commenting in crude language about how his celebrity status allowed him to force himself on women prompted numerous women to come forward with accusations about his past inappropriate sexual conduct. Trump dismissively called the recording “locker room talk” and disputed the accusers’ claims.

But his unexpected victory over his Democratic opponent, Hillary Clinton—the first female presidential nominee of a major party in U.S. history—outraged and saddened many who objected to his past treatment of and statements about women, as well as his controversial positions and rhetoric during the campaign.

The idea of the Women’s March began on the social networking website Facebook the day after the election, when a Hawaii woman named Teresa Shook voiced her opinion that a pro-woman march was needed as a reaction to Trump’s victory. After thousands of women signed up to march, veteran activists and organizers began planning a large-scale event scheduled for January 21, 2017, the day after Inauguration Day.

Leading up to the Women’s March on Washington, the organizers expected some 200,000 people to attend. As it turned out, as many as 500,000 showed up, with buses, trains, airplanes and packed cars ferrying large groups of protesters to the capital from far-flung locations. Many of the marchers donned pink clothing for the occasions, as well as the unofficial uniform of the march: pink knit hats with cat-like ears on top, dubbed “pussy hats” in a nod to Trump’s word choice in the 2005 recording.

On the same day, millions more people took part in sister marches held in all 50 states and more than 30 foreign countries, ranging from Antarctica to Zimbabwe. According to later estimates collected by the Washington Post, some 4.1 million people reportedly took part in the various Women’s Marches across the United States, along with around 300,000 worldwide.

In New York City—Trump’s hometown—some 400,000 people marched up Fifth Avenue, while in Chicago the crowd grew so large (more than 150,000) that organizers called off the march and rallied in the city’s Grant Park instead. Los Angeles reportedly saw the largest demonstration in the country, with as many as 750,000 demonstrators. Despite the size of the demonstrations, they remained largely peaceful, with no arrests reported in Washington, D.C., and only a handful in other cities.

The protesters who took part in the various Women’s March events voiced their support for various causes, including women’s and reproductive rights, criminal justice, defense of the environment and the rights of immigrants, Muslims, LGBT people and the disabled—all of whom were seen as particularly vulnerable under the new administration.

Rather than a single-day demonstration, the Women’s March organizers and participants intended their protests as the start of a resistance movement. After the march in Washington, D.C., organizations like EMILY’s List and Planned Parenthood held workshops designed to encourage civic participation among women, including running for office.

And in October 2017, MarchOn, a progressive group founded by march leaders from around the country, launched a Super PAC as part of its efforts to create political change, including mobilizing supporters to vote in the 2018 midterm elections and beyond.

“At 2.6 million strong, Women’s Marches crush expectations,” USA Today, January 22, 2017.
“Shaded pink, women’s protest fills the streets of downtown L.A.,” Los Angeles Times, January 22, 2017.
“This is what we learned by counting the women’s marches,” Washington Post, February 7, 2017.
The March, Women’s March website.