International Women's Day was founded more than a century ago in the early 1900s when 15,000 women marched in New York City, demanding better working conditions and voting rights.

Today, women are celebrating their achievements while calling for gender equality.

UK Prime Minister Theresa May tweeted:

The Eiffel Tower even lit up with the hashtag "times up" written in French.

Barbie released an Inspiring Women line featuring women like pilot Amelia Earhart, NASA and mathematician Katherine Johnson, and modern day gold medalist snowboarder Chloe Kim.

And Kim tweeted what an honor it was to be recognized in such a way.

Other brands are getting in on the marketing opportunity. A McDonalds in Lynnwood, Calif., flipped its golden arches upside down to make a W.

Worldwide, women are standing up for what is right and highlight some of the injustice they have faced. Hundreds of South Koreans, many wearing black and holding black #MeToo signs, rallied in central Seoul.

South Korea’s #MeToo movement has gained significant traction since January, when a female prosecutor began speaking openly about workplace mistreatment and sexual misconduct. The list of women who speak out is growing day by day.

Several high-profile South Korean men have resigned from positions of power, including a governor who was a leading presidential contender before he was accused of repeatedly raping his female secretary.

This year's International Women's Day theme is Press for Progress. Men and women are sharing how they plan to press for progress for women, by filling out cards and posting on social media.

You can find a link to the cards here.

The Associated Press contributed to this story.