اربعین is a significant religious observance in the Islamic tradition, particularly among Shia Muslims. It marks the end of the mourning period for the martyrdom of Imam Hussein, the grandson of the Prophet Muhammad, who was killed in the Battle of Karbala in 680 CE. This day falls on the 20th of Safar in the Islamic lunar calendar, 40 days after Ashura, the day of Imam Hussein's martyrdom. During اربعین, millions of pilgrims travel to the holy city of Karbala in Iraq to pay their respects at the shrine of Imam Hussein. The event is characterized by processions, prayers, and acts of charity, reflecting themes of sacrifice, justice, and remembrance. It serves as a powerful reminder of the values upheld by Imam Hussein and his stand against tyranny.