The Arba’een Pilgrimage is the world’s largest annual public gathering held every year in Karbala, Iraq at the end of the 40-day mourning period following Ashura, the religious ritual of the martyrdom commemoration of the grandson of the Prophet Mohammed and the third Shia Imam, Husayn ibn Ali 680.
Over 10 million
|Arba’een Pilgrimage||20 Oct 2019||70–80 million||Karbala||Iraq|
|Kumbh mela||4 February 2019||50 million||Prayagraj||India|
|Kumbh Mela||10 February 2013||30 million||Prayagraj||India|||
|Arba’een Pilgrimage||2018||30 million||Karbala||Iraq|||
|Arba’een Pilgrimage||2016||20–30 million||Karbala||Iraq|||
|Arba’een Pilgrimage||2015||27 million||Karbala||Iraq|||
|Arba’een Pilgrimage||2014||20 million||Karbala||Iraq|||
|Kumbh Mela||30 January 2001||20 million||Prayagraj||India|||
|Arba’een Pilgrimage||January 2013||15–18 million||Karbala||Iraq|||
|Arba’een Pilgrimage||January 2012||15 million||Karbala||Iraq|||
|Arba’een Pilgrimage||January 2011||15 million||Karbala||Iraq|||
|Funeral of C. N. Annadurai||February 1969||15 million||Tamil Nadu||India|||
|Kumbh mela||15 January 2019||14 million||Prayagraj||India|||
|Arba’een Pilgrimage||2017||14 million||Karbala||Iraq|||
|Aalmi Ijtema Aurangabad||2018||12.6 million||Aurangabad, Maharashtra||India|||
|Martyrdom processions of Musa al-Kadhim||2016||12 million||Kadhimiya, Baghdad||Iraq|||
|Martyrdom processions of Musa al-Kadhim||2015||12 million||Kadhimiya, Baghdad||Iraq|||
|Funeral of Ruhollah Khomeini||11 June 1989||10.2 million||Tehran||Iran|||
|Arba’een Pilgrimage||January 2010||10 million||Karbala||Iraq|||
|Arba’een Pilgrimage||2009||10–14 million||Karbala||Iraq|||
Five million to ten million
About 7-9 million were gathered in Karbala, Iraq to celebrate the anniversary of Imam Hussein in October 2015.
An estimated 7.5 million people gathered in New York City, USA on April 20, 1951, to honour General Douglas MacArthur, just 15 days after being released from President Truman.
An estimated 6 to 7 million attended the Mass in Rizal Park, Manila, on January 18, 2015, which ended apostolic and state visits by Pope Francis in the Philippines. It was held at the Santo Niño feast and is the largest papal audience in history.
Over 6 million people gather at Karbala on July 6, 2012, to celebrate 15 Sha’ban.
An estimated 6 million worshipers gathered at the shrine of Imam Hussein in Karbala on August 8, 2009, during Mid-Sha’ban. 
Over 5.5 million stood for Traslación of the Black Nazarene 2015 in Manila, Philippines, prior to Pope Francis’ visit.
More than 5 million pilgrims went to Karbala in the sanctuary of Imam Husain on July 15, 2011, on the 15th Shaban (Mid Shaban).
Over 5 million people attended World Youth Day 1995 in Manila, Philippines to meet Pope John Paul II. It was the largest papal crowd in history until it was surpassed on January 18, 2015, during Pope Francis’s also in Manila.
An estimated 5 million people participated in the Democracy and Martyrs Rally in Istanbul on August 7, 2016, according to the Istanbul Police Department.
More than 5 million people participated in the 2016 World Series parade in Chicago, Illinois, after the Chicago Cubs won their first World Series since 1908.
The Chicago Cubs 2016 World Series victory paired and attracted over 5 million people.
Two to five million
4 million pilgrims visit the Imam Ali Shrine in Iraq on the anniversary of the martyrdom of the first Shia Imam on June 28, 2016.
More than 2 million Muslims gather for the important ritual as part of Hajj 2016.
An estimated 2.8 million people made the annual Hajj to Mecca, Saudi Arabia (excluding unregistered pilgrims that were over 0.75 million, the number of pilgrims would then be over 3.5 million) in November 2010.
An estimated 5 million pilgrims gathered to mourn the death anniversary of Imam Kazim at the Al-Kadhimiya Mosque in Kadhimiyah on June 30, 2011.
An estimated 5 million people attended the funeral of Egyptian President Gamel Abdel Nasser on October 1, 1970, in Cairo, Egypt.
An estimated 5 million dedicated people participated in Bishwa Ijtema in Bangladesh in 2010.
An estimated 5 million people gathered in Sabarimala, India on January 14, 2007, to watch “Makarajyothi”, a bright flame flickering three times on a remote slope of Ponnambalamedu.
An estimated 4.2 million people attended a concert given by Rod Stewart in Rio de Janeiro, Brazil on December 31, 1994.
Over four million people flocked to Karbala on Ashura Day at the shrines of Imam Hussein and his younger paternal half-brother Abbas in 2010.
An estimated four million people attended the funeral of Umm Kulthum in Cairo, Egypt on February 6, 1975.
An estimated 3.5 million people attended the concert given by Jean-Michel Jarre for the celebration of Moscow’s 850th anniversary in 1997. [quote needed]
An estimated 3.16 million people made the annual Hajj to Mecca, Saudi Arabia in 2012 (1.4 million Saudis and 1.75 million foreigners)
An estimated 3.2 million people gathered for the annual celebration of Santo Niño de Cebú (child [Jesus] of Cebu) on the third Sunday of January 2014. The audience participated in the solemn procession on the main streets of Cebu City, Philippines.
3 million Shia Muslims Celebrate Anniversary of Muhammad’s and Imams Hassan’s Death in Najaf at the Sanctuary of Imam Ali on 28 Safra (February 3) 2011
Over three million renewed loyalty pledges to Imam Ali in Najaf on November 16, 2011
More than 3 million devotees had gathered in the first Nabakalebara Ratha Yatra in the millennium in Puri, India, which took place after a gap of 19 years.
3 million break their celebrations at Imam Reza Shrine of Iran at Ramadan July 13, 2013, the world’s largest iftar ever.
More than 3 million people visited the shrine of Imam Reza in Mashhad, Iran during the Nowrooz weekend.
An estimated 2.5 to 4.5 million people gathered for the funeral of Iran’s ex-president Akbar Hashemi Rafsanjani in Tehran on January 10, 2017.
More than 3 million people protested in Circus Maximus, Rome, on March 23, 2002, in a demonstration organized by the leftist trade union CGIL, led by Sergio Cofferati, against the labour reform promoted by the Conservative government Silvio Berlusconi.
An estimated 3 million people marched through Rome, Italy in opposition to the US-led invasion of Iraq in the largest anti-war rally in history on February 15, 2003.