Saddam Hussein, (a Sunni who ruled as an Arab nationalist, clashing with Islamic revivalism) was president of Iraq. For nearly 30 years under Saddam's regime, it was forbidden to mark Arbaʽeen publicly in Iraq. Following the 2003 invasion of Iraq, the observance in April 2003 was broadcast worldwide. Annual pilgrimage The city of Karbala in Iraq is the center of the proceedings which many pilgrims travel miles on foot to reach. As of 2016 "between 17 million and 20 million" pilgrims usually attend Arba'ein there, including about three million foreigners, most of whom are Iranians. Arbaʽeen is consistently among the largest peaceful gatherings in history. Every year, huge crowds of pilgrims travel to the city of Karbala in pilgrimage to the Imam Hossein holy shrine in Karbala on Arbaʽeen Day. (For example, it is over 500 km from Basra the largest city in southern Iraq where Shia predominate to Karbala.) It is traveled annually on foot by Iraqi pilgrims, which takes them two weeks, or approximately one month to come from other countries like Iran. The crowds become so massive that roads are blocked for hundreds of miles. In 2008, approximately nine million religious observers converged on Karbala to commemorate Arba'ein. In 2009, over ten million people were estimated to have reached Karbala, according to BBC News and Press TV. In 2013, 20 million pilgrims from 40 countries came for Arba'ein, according to Iranian media. A car bomb targeting worshippers returning from Karbala killed at least 20 Shiite pilgrims in January 2013. In 2014, up to 17 million people made the pilgrimage and many choose to make the 55-mile journey on foot from Najaf, near areas controlled by the militant Islamic State of Iraq and the Levant (ISIL), which has declared Shia Muslims apostates. Up to 17 million pilgrims came in 2015 and 2016. Ziyarat of Arba'ein The Ziyarat Arba'ein is a prayer which is usually recited in Karbala on the day of Arba'ein. It is narrated from Safwan al-Jammaal from Imam Ja'far al-Sadiq, the sixth Shiite Imam, in which the Imam instructed him to visit Imam Husayn's mosque, and to recite a specific visitation prayer on Arba'ein by which the believer should reaffirm their pledge to Husayn's ideals. The Ziarat or prayer is a text which designates Husayn as the "inheritor" of the prophets Adam, Noah, Abraham, Moses, Jesus and Muhammad. Peace be on the favorite of Allah, Peace