Traditionally, the Day of Arbaeen has been commemorated by
millions of people around the world through holding mourning
processions to pay tribute to the sacrifice of Imam Hussain for social
justice. Typically, on this day people organize large marches in cities
across the world to symbolize the eternal nature of Imam Hussain’s
Revolution and to show they stand for social justice and honor.
https://scmw.atu.ac.ir/article_10140_bf84029e9ac44368f85600d34df9d59f.pdf