Cecile Richards is president of the Planned Parenthood Action Fund. The opinions expressed in this commentary are solely those of the author.

(CNN) One year ago, I took a flight from Miami to Washington, hoping to arrive in time for the Women's March the next morning. Our flight attendant leaned over to me and asked, "Do you think it's going to make any difference, this march?" She wore a pin commemorating her 20 years of airline service, and I could hear the skepticism in her voice. I understood her uncertainty -- was the anger and passion shared by so many women across America in the wake of the 2016 presidential election enough to inspire real change?

The truth was, I had no idea.

Cecile Richards

As we found out, no one could have predicted the magnitude of the next day. Marches erupted across the country and on every continent. Several reports said it was likely the largest demonstration on record in the United States, dwarfing the inaugural crowd the day before. By some estimates as many as 4 million people just felt they had to march. So they picked up their signs, left home and spoke with their feet.

So many people remember where they were that day. In Washington, marchers packed the National Mall for as far as the eye could see. And it wasn't just women, either. Folks from every walk of life came out to say, "This is my issue, too." A young man carried one of my favorite posters: "I'm proud to be marching with the future president of the US -- I don't know who she is, but I know she is here!"

Beyond Washington, thousands of people held up signs in Salt Lake City, record-breaking crowds gathered in Texas, and Alaskans of all ages weathered subzero temperatures in Fairbanks to show their support. The best part is that these marches were just the beginning.

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