Tuesday, April 4, is Equal Pay Day, the day symbolizing how far into the year women must work to earn what men earned in the previous year and observed by activists and advocates as an occasion to raise awareness about the gender pay gap.

Several organizations offer suggestions on how to commemorate Equal Pay Day. For example, the American Association of University Women (AAUW), an organization devoted to promoting equity and education for women and girls, offers several “easy ideas for marking Equal Pay Day” and “ways to take any Equal Pay Day to the next level.” The AAUW also offers sample materials, such as an “Equal Pay Day Proclamation.” Similarly, the American Bar Association’s (ABA’s) Gender Equity Task Force suggests the “top six ways to show support for equal pay.” Number one on the ABA’s list: wear red to show “support for women who have been ‘in the red’ to their male counterparts since the end of the previous year.”

Equal Pay Day has become more recognized around the world. In the U.K., the Telegraph posted 14 designs created by social media users to visualize the gender pay gap, such as the one below.

Some have decried the “celebration” of this symbolic day (“’Happy Equal Pay Day,’ said No Woman Ever”). On Equal Pay Day 2016, Senator Elizabeth Warren (D-Mass.), in a speech on the Senate floor, called it “a national day of embarrassment”: “Today is Equal Pay Day, and by the sound of it, you would think it’s some sort of historic holiday commemorating the anniversary of a landmark day that our country guaranteed equal pay for women. But that’s not what this is about. Not even close.”