In the largest foot march in the world, millions of Shia Muslims from different countries set off to participate in the Arbaeen march in Karbala on the 20th of Safar every year. Despite the high September temperatures in Iraq, millions of visitors flocked to Karbala from various countries, the most important of which is Iran. Iraq opened its borders to Iranian visitors without a visa requirement for entering the country; about 5 million visitors have entered Iraq so far to participate in the Arbaeen pilgrimage. Fifteen million participants come from all other Iraqi provinces. The Iraqi Minister of Interior predicted the number of Arbaeen participants to reach about twenty million. The Ministry of Interior has prepared accommodation for visitors participating in the Arbaeen pilgrimage from sleep, food, treatment, and all means of comfort. Arbaeen marks the end of the forty-day mourning period for the death of Imam Hussain. The pilgrimage takes place forty days after Ashura, in which Shia Muslims worldwide participate in a foot march from Najaf to Karbala in Iraq.