International Women’s Day is today and it’s being observed by all kinds of entities—governments, schools, charities, and companies—throughout the world.

Here’s everything you need to know about the day celebrating half of the world’s population.

What is the meaning of International Women’s Day?

International Women’s Day is a global day to celebrate the achievements of women, and a call to action for gender equality.

Why do we celebrate on March 8?

According to the International Women’s Day’s website, a day for women was first marked in 1909 by the Socialist Party of America on Feb. 28. The following year, the leader of the ‘Women’s Office’ for the Social Democratic Party in Germany, Clara Zetkin, proposed the idea for an International Women’s Day at an International Conference of Working Women.

A number of countries adopted the day, initially celebrating it on March 25. In 1913, it was decided to transfer the day to March 8, where it has remained ever since.

The United Nations adopted International Women’s Day in 1975, helping the day gain wider reach.

What is the theme for 2019 International Women’s Day?

The theme this year is #BalanceForBetter, which seeks to create a more gender-balanced world. Balance is more than just a women’s issue—it’s a business issue. “Gender balance is essential for economies and communities to thrive,” explains the IWD website.

What color do you wear?

Purple is the international color symbolizing women.

How do you celebrate?

The IWD website calls on everyone to carry on the work of the suffragettes, and “recognize, honor and celebrate” the achievements of women across the world.

Some companies will mark the day with promotions, campaigns, and events and individuals can chime in on social media. A range of events are listed on the IWD website.