Millions of Muslims from across the world are converging on Iraq’s holy city of Karbala to mark Arba’een.
People from 60 countries have marched to Karbala this year to pay tribute to Imam Hussein. Some 2 million Iranians are among those attending the ceremony. Many people inside Iraq have marched for days to join the event. Arba'een, which is known as one of the world's largest religious gatherings, fell on November 21 this year. It marks the 40th day after the martyrdom anniversary of Imam Hossein, the grandson of Prophet Mohammad.