The second day of the Trump administration has seen an unprecedented wave of protests swell across the globe, as the Women's March on Washington and its sister marches on all continents—yes, including Antarctica—fight back against the U.S. president's frightening rhetoric.

Organizers' informal tally now puts the total number of march participants at a stunning 2.5 million around the world. And with an estimated 500,000 marchers on the National Mall in Washington, D.C., the Women's March is now the largest inaugural protest in U.S. history.

Participants and journalists are capturing the international upswell of protest:

Largest crowd I've ever seen in 33 years in Anchorage and it's 15 degrees and white out conditions. pic.twitter.com/oFvpUIm8JW — Diane Kaplan (@DianeSKaplan) January 21, 2017

The #WomensMarch in downtown St. Louis! This is what democracy looks like. pic.twitter.com/mzb5xMZUKC — Antonio French (@AntonioFrench) January 21, 2017

A solidarity march in Kolkata, Buenos Aires, Barcelona and Sydney #WomensMarch https://t.co/bUsKlw2OZb pic.twitter.com/YgiKrbeEYr — Mijwan in Denmark (@mijwandk) January 21, 2017

The woman next to me on the plane was handed this by the flight attendant. #WomensMarchOnWashington #WhyIMarch pic.twitter.com/PjlL9H59KR — Candice with an L (@artist4ever) January 21, 2017

Yes. The future depends on it. #WomensMarch pic.twitter.com/6edof8TZGz SCROLL TO CONTINUE WITH CONTENT Never Miss a Beat. Get our best delivered to your inbox.





— ChuckModi (@ChuckModi1) January 21, 2017

In the tiny town of Alpine Texas, the women's march marched up a mountain: pic.twitter.com/NhCMpYKYLH — Anne Helen Petersen (@annehelen) January 21, 2017

On social media, march participants are also using the hashtag #WhyIMarch to talk about what compelled them to take to the streets:

#whyimarch Tweets