Around 9 a.m. in Arlington, Virginia, the D.C. metro had already slowed to a crawl — weighed down by the hundreds of thousands of demonstrators in pink knitted caps heading towards the Washington Mall in Washington, D.C., for the Women’s March on Washington. At the entrances to the metro across the District and its surrounding suburbs, locals clustered in solidarity, handing out cookies and pussyhats mailed in from women who couldn’t make it to the march but wanted to show their presence. Underground, the masses filed politely onto trains heading towards the Capitol Hill area — though cramped, it was positively roomy compared with your average commute-hour crowd in the New York subway.

The atmosphere was electrifying, even at an early hour — positive energy rippled through the underground. If there was any lingering suspicion that demonstrators were divided in the lead-up to the demonstration, it was dispelled within moments of arrival. Strangers beamed at each other, even when they toppled into one another as the metro lurched to a stop — and even though we were waking up for the first time with Donald Trump in the White House. Ten minutes into the 45-minute commute (15 minutes, on a normal day), my eyes started to well up, the first of many times that day. I wasn’t alone — and I wasn’t the only one on the verge of tears.

We tumbled out into an overcast late-morning D.C., swept up in a current that washed us towards the Washington Mall. A jumbotron around the corner from Bobby Van’s, just north of the White House, flashed: “Special Event Downtown”; “Avoid Delays”; “Use Metro” — in case anyone had missed the headlines. The headless mass spilled south — though no one seemed to know the destination, it grew denser and more energized as the Washington Monument loomed into sight. Infants in insulated onesies and knit caps perched on their parents’ shoulders; groups of high schoolers trotted past with hand-painted signs ranging from the pro-woman (illustrations of uteruses and quotes attributed to Michelle Obama, Gloria Steinem, and Eleanor Roosevelt populated posterboards) to the anti-Trump (“Ceci N’est Pas un Président” was a highlight) and everything in between (“Pussy Grabs Back” and “Nasty Woman,” both inspired by the president’s misogynist rhetoric, made numerous appearances).

On Independence Avenue, outside the Hirshhorn Museum, a succession of speakers filed onto the stage: Gloria Steinem, Cecile Richards, Janet Mock, and the co-founders of the Women’s March; Madonna and Alicia Keys both performed. There, the crowd grew so thick it was impossible to move, but on the Washington Mall just north, those who couldn’t hear the words of the planned program hosted their own rallies. Young women like Jamaica Ponder and Preyel Patel climbed onto trucks parked on the lawn, hyping up the crowd below them. Their chants matched the plurality of the crowd they addressed, moving seamlessly between slogans in favor of reproductive rights to Black Lives Matter to immigrant rights — with the occasional reference to our “Cheeto-in-chief” for good measure.

Since its inception Nov. 9, the Women’s March evolved from a demonstration promoting gender equality in the face of a president-elect who has confessed to sexual misconduct to a massive movement encompassing a range of overlapping interests including civil rights, gun control, reproductive rights, climate justice, and more. Its organizers detailed the symbiosis of these wide-ranging concerns in the Unity Principles released a week before the march — and that synthesis came to life on the green of the Washington Mall, where it didn’t matter what your sign read, what your chant sounded like — you’d hear voices chiming in, hear footsteps marching alongside.

Or, perhaps, shuffling alongside — around 2:30, a rumor rattled the crowd, fighting their rebelling cell service to access Twitter updates. The march had drawn so many attendees, we heard — more than double the anticipated 200,000 — that they filled the planned route down Independence Ave. to the Ellipse in front of the White House. There were too many people to march — a fact that, while disconcerting for those who were eager to simply get on with it, was also welcomed as an indicator of the sheer strength of showing of solidarity that day. Friends turned to each other, wondering aloud at the volume of bodies surrounding them.

But the crowd down Independence also grew antsy, chanting “March!” over speeches by Angela Davis, Trayvon Martin’s mother Sybrina Fulton, and Janelle Monáe, who performed her protest anthem “Hell You Talmbout” while surrounded by the mothers of the Black Lives Matter movement. A white-haired woman turned to me as I checked my phone for service. “Can you Twitter the group and tell them to be quiet and let the march start?” she asked me. As if on cue, one of the organizers seized the microphone. “You may have heard we’re not marching,” she announced. “We are marching.” And with that blessing, and a whoop of excitement, the crowd surged forward.

Still, the march trudged along so slowly, it was possible to stop for coffee and rejoin the masses without missing a moment. In line at the café at the Smithsonian Museum, a 78-year-old Chicagoan named Irene Zaun speculated about the crowd sizes. Estimates drifted through the crowd, which, depending on who you consulted, numbered anywhere from 250,000 to 1.2 million strong. Zaun, a white-haired former high school teacher, had seen crowds like this back in the ’70s when she protested the Vietnam War. She was heartened, she said as she filled a paper cup with steaming coffee, to see so many young people joining this movement — “We’re over the hill,” she said with a laugh, gesturing to a few other septuagenarians in line.

Caffeinated, I rejoined the crowd as it rounded a corner towards the White House. A woman wafted burning sage through the air on the lawn out front. A shrine of discarded signs dangled from a fence barricading the demonstrators from approaching any closer —signs that have since been reclaimed by several museums for preservation.

But even after the climax of reaching the White House, the march wasn’t over: Cross the street, and another cohort of demonstrators might be bearing down on you. A bus charged down H Street, passing a huddle of marchers en route to the metro. A man pressed his face to the window as it drove past, thrusting his arm out an opening, middle finger extended. “Fuck Trump!” he cried; a cheer went up from the sidewalks. Around another corner, a throng of 200 or so 20-somethings marched down the street, many of them nearly skipping with energy, brandishing signs and chanting. A few police officers on bicycle chaperoned this mini-march, a rare, brief sighting of police presence on a day that, remarkably, yielded no arrests. (It was impossible not to think that this group, having splintered from the primary march, had been singled out for escort because it comprised largely young people, many of them men and women of color.) The energy was still palpable at 7 p.m., hours after the march’s scheduled end time. Pockets of friends and families gradually dispersed, returning home after an energizing, exhausting day. As the night drew on, bars filled with young people excitedly recapping the day’s events. The lingering vigor seemed to indicate that this would be a movement that outlasted the day alone — that, galvanized by the sheer turnout at the Women’s March, these protesters might show up next time, too.

At the end of it all, outside the MacPherson metro station, a young woman stood on a street corner, urging vigilance: “Stay involved,” she cried out. “Go online.”

Meet the women who organized the history-making Women's March on Washington: