The Shrines of Husayn and al-Abbas, Karbala

Karbala is central to Shia practice specifically, and saying so is not a technicality.

Sunnis honour Husayn as the grandson of the Prophet and as a martyr. But the mourning observances built around his death, the pilgrimage economy around the shrines, and the theology of redemptive suffering and intercession that goes with them are Shia, and they are among the practices that most sharply distinguish Shia religious life.

What happened, and how it is remembered

On 10 Muharram 61 AH - 10 October 680 CE: Husayn, with his family and a band of perhaps seventy-two companions, was surrounded at Karbala by the army of the Umayyad caliph Yazid, cut off from the Euphrates, and killed. The survivors, chiefly women and children, were taken captive to Damascus.

Shia tradition does not treat this as a military defeat to be regretted but as the defining moral act of the tradition: the deliberate choice of righteous death over allegiance to an unjust ruler, made in full knowledge of the outcome. The often-quoted formulation, that every day is Ashura and every land is Karbala, makes it a permanent template rather than a past event.

Ashura is marked with recitation of the events, processions, passion plays, and in some communities self-flagellation, a practice that some senior Shia authorities have discouraged or forbidden, directing the faithful toward blood donation instead. That is one of several internal Shia disagreements about how the day should be observed.

Destroyed, repeatedly

• c. 850 CE: the Abbasid caliph al-Mutawakkil had the shrine demolished and the ground ploughed and planted, an attempt to obliterate the grave rather than merely close it, and to stop the pilgrimage.
• 1802: Wahhabi raiders sacked Karbala, killing large numbers and stripping the shrine of its gold and silver, on the grounds that veneration at tombs is idolatry, the argument later applied at Jannat al-Baqi.
• 1991: Saddam Hussein's forces heavily damaged the shrine while suppressing the Shia uprising after the Gulf War. Repairs ran to 1994.
• Since 2003, Sunni jihadist groups have repeatedly bombed the pilgrimage and its routes.

The pattern is worth noticing: the site has been attacked by an Abbasid caliph, by Wahhabi raiders, by a Baathist government and by jihadists, for reasons that were in turn political, theological, political and both.

Arbaeen

Forty days after Ashura, the Arbaeen pilgrimage brings crowds counted in the millions to Karbala, many walking the eighty kilometres from Najaf over several days, fed and housed along the road by villagers who set up free stations for the purpose.

It was suppressed under Saddam and resumed after 2003. It is generally described as the largest annual gathering of human beings anywhere on earth, and it takes place with almost no formal organisation and against a standing risk of attack.

The attendance figures, usually given as somewhere above twenty million, originate with the shrine custodians and with Iraqi and Iranian state media, and no independent count has been made or methodology published. That the gathering is enormous is not in doubt. The precise arithmetic is assertion rather than evidence, and this atlas repeats it as such.

The attendance figures, usually given as somewhere above twenty million in recent years, should be read with the knowledge that they originate with the shrine custodians and with Iraqi and Iranian state media. No independent count of the Arbaeen crowd has ever been made and no methodology for the published figures has been released. That the gathering is enormous is obvious to anyone who has seen it; the precise arithmetic is not evidence, it is assertion.

Karbala's shrines have been destroyed by fellow Muslims more than once, and the walking pilgrimage now held there each year is among the largest gatherings of human beings anywhere on earth.

Torn down by a caliph

In 850 the Abbasid caliph al-Mutawakkil, hostile to the growing pilgrimage tradition at Husayn's grave, ordered the shrine demolished and the site ploughed and flooded to discourage visitors, a deliberate act of religious suppression rather than incidental war damage. The shrine was later rebuilt once political conditions changed, only to be sacked again in 1802 by Wahhabi forces from the Arabian interior, who killed a large number of residents and looted the shrine's treasury.

Arbaeen

Forty days after Ashura, pilgrims mark Arbaeen, commemorating the end of the traditional mourning period for Husayn, with a mass walking pilgrimage along the road from Najaf to Karbala. In recent years the gathering has drawn well over ten million participants, organised substantially through free roadside hospitality provided by volunteers along the route, making it one of the largest annual peaceful gatherings recorded anywhere, larger by attendance than the Hajj itself.

Security remains a live concern

The shrines have faced repeated threats from sectarian violence in recent decades, including during the period of Islamic State's territorial control in parts of Iraq, and remain under heavy security to this day, a precaution the site's history of deliberate destruction makes far from theoretical.