Hundreds of Women's Marches Planned Worldwide The main event in D.C. is expected to draw more than 200,000 participants.

 -- Less than 24 hours after President Donald Trump was sworn into office, tens of thousands of people gathered in the U.S. capital for the Women’s March on Washington.

Outside of Washington, D.C., so-called sister marches are taking place in every state across the nation and in dozens of countries around the world.

“It was clear from week one this was going to be a global movement,” said Evvie Harmon, co-founder and global coordinator of the Women’s March on Washington. “It’s like the women of the world were sitting on a powder keg and Donald Trump lit the match.”

Some 673 sister marches are planned worldwide. Total attendance could surpass 2.5 million, based on online RSVP estimates, according to the Women’s March on Washington website. The marches spanned all 50 U.S. states, several U.S. territories and at least 60 countries across all seven continents.

Organizers said the sister marches are solidarity events inspired by the Women’s March on Washington and planned by volunteers around the globe. These marches are taking place “as part of a united proactive international stance on women’s equality worldwide,” according to a press release from Women’s March Global.

Sister Marches Across U.S. Cities

Organizers of the Women’s March on Washington urged people around the globe to join or host a sister march if they can’t make it to the U.S. capital.

One of the largest is taking place in New York City, where participants will end the march at Trump Tower in Midtown Manhattan. The marchers carried signs in support of women's rights, climate change and LGBT rights.

There isn't an official estimate on the number of marchers in New York City, but organizers told ABC News the crowd size exceeds the 150,000 participants who registered. The New York City Police Department told ABC News it made a last-minute decision to close parts of Madison Avenue to accommodate the larger than expected turnout.

In Massachusetts, organizers anticipated as many as 80,000 participants for the sister march in Boston, according to ABC affiliate WCVB. Democratic Sen. Elizabeth Warren, a harsh critic of Trump, was among the speakers at the event.

"Now we can whimper, we could whine or we could fight back. Me, I'm here to fight back," Warren said amid cheers from the crowd.

In Georgia, thousands are expected to participate in the women’s march in downtown Atlanta this afternoon, according to ABC affiliate WSB-TV.

Ramona Brant of Charlotte, North Carolina, traveled to Washington, D.C., for the women’s march. But a sister march is also taking place in her hometown Saturday morning.

“We want to be respected and honored in our position in corporate, as mothers and we don’t want to be disrespected by any man anywhere at any time,” Brant told ABC affiliate WSOC.

Leah Charney of Colorado said she’ll be participating along with her family and friends in a sister march planned in Denver.

"For me, it’s about showing up and being counted and being visible," Charney told ABC affiliate KMGH on Friday night while working on her sign for the rally.

The event’s organizers told KMGH the Denver rally isn’t just about women’s rights, but also about supporting all human rights, minorities and other marginalized communities.

In Chicago, as many as 75,000 were expected to participate in the march. The organizers said they’ve been in “constant contact” with the Chicago Police Department as well as city officials to ensure a peaceful demonstration.

"It's about more than the election of the president; it's about the mindset which led to his election." organizer Jessica Scheller told ABC affiliate WLS.

Sister Marches Around the Globe

Meanwhile, sister marches took place in South America, Africa, Europe, Asia, Australia and even Antarctica, according to organizers.

In Kenya, organizers of the march in Nairobi cited Trump’s election as a threat to human and civil rights.

"The recent elections in the United States have shown how real the threat is to our collective rights and liberties,” the organizers stated on the event’s Facebook page. “We march together for the protection of our rights, our safety, our families, our health and the health of our planet—recognizing that our vibrant and diverse communities are the strength of our society.”

Tens of thousands of people were expected to participate in the women's march in London, based on the event's Facebook page. Live stream footage of the rally posted on the event's website showed the crowd -- men, women and children -- marching and chanting in the streets.

"I'm just here to be counted," one participant said on the live stream.

"I'm here because everyone should be here," another marcher said. "I think at the moment politics is disgusting. We need less hate, more love."

In Germany, marchers descended on Berlin, saying they “will not rest until women have parity and equity at all levels of leadership in society,” according to the event’s Facebook page.

Gloria Steinem, who addressed the Women’s March on Washington, relayed a message to Americans from the marchers in Germany: “We in Berlin know that walls don’t work.”

In Czech Republic, hundreds gathered in freezing temperatures for the march in Prague, waving portraits of Trump and Russian President Vladimir Putin and carrying banners that read, "This is just the beginning," "Kindness" and "Love."

"We are worried about the way some politicians talk, especially during the American elections," organizer Johanna Nejedlova told The Associated Press.

In Australia, thousands of people marched in solidarity in Sydney, according to the AP. Organizers stated on the event’s Facebook page that they are marching “to raise our voices in defense of women’s rights and against hatred and bigotry.”

ABC News' John Bentley and Mara Schiavocampo contributed to this report.