The Arafa Day, which falls on the 9th day of Dhul Hijja of the lunar Islamic Calendar, is considered a sacred time for Muslims to fast and perform prayers.
On this day Muslims around the world stand in supplication and devotion, praying for God's abundant forgiveness.
Muslims gather to make repentance and seek God's mercy, recite words of prayers and remembrance, and gather together as equals. A prayer called "Arafa Prayer" composed by Imam Hossein, Shiite Muslims' third Imam (Prophet Mohammad's grandson), is uttered on this day.
Iranian Muslims are out in Tehran, praying, and preparing for Arafa Day rituals. Similar ceremonies are also held in other cities throughout the country.
This is the day which comes before one of Muslims biggest religious festivals, called Eid-al-Adha (Feast of the Sacrifice).
Every year, Iranians, like other Muslims around the world, hold special ceremonies to observe the auspicious days.
This year, the religious festival falls on Sunday, October 5th in Iran.
People from different walks of life will go to mosques to participate in Eid al-Adha prayers. They will also sacrifice sheep and cattle to celebrate the “Festival of Sacrifice.”