Shi'ite Muslims all over the world have been beating themselves with sharp blades, covering their bodies in mud and lighting bonfires in the streets to mourn the death of the Prophet Muhammad's grandson today.
Photographs from Delhi, India, showed shockingly young boys lashing their own backs with small knives and chains.
Thousands of men performed the same brutal practice in Lebanon, Bangladesh, Iraq, Pakistan and Myanmar and even Athens, Greece.
The bloody rituals were part of the holy Day of Ashura, when Shi'ite Muslims remember the death of Imam Hussein at the Battle of Karbala in 680 AD.
Shi'ite devotees wiped the tears from their eyes as the listened to the accounts of Hussein's death under the golden dome of Imam Hussein's mausoleum in Karbala, Iraq.
Thousands of Muslims from neighbouring Iran visit the shrine, which lies around 50 miles from the capital Baghdad, every year.
Millions across the globe, from Lebanon to south-east Asia, hold processions in their home towns and take part in a variety of rituals.
Some beat their backs to a drumbeat using chains or blades, while others beat their heads with a sword until blood drenches their faces and white 'mourning robes'.
Karbala and other cities hosted reenactments of what Shi'ites refer to as Hussein's martyrdom, complete with horseback warriors and the annual 'mud rubbing' ceremony took place in Khorramabad, southern Iran.
Hundreds of men and women jumped into vats of wet mud before standing by huge bonfires lit in the middle of the streets to dry it on their skin and clothes.
'Mud Rubbing' is a traditional ceremony that is held in the city of Khorramabad every year to commemorate the Ashura day.
The Day of Ashura - which is the tenth day of the 'mourning month' of Muharram has been marred by attacks targetting Shi'ite Muslims in the past and Iraq deployed tens of thousands of security forces across the country this year.
They formed three concentric security rings around Karbala, banned traffic in the city centre three days ago and used special explosive detection equipment.
The measures were aimed at reducing the risk of suicide bomb attacks by ISIS, who claim to be a Sunni group although governments of the world have rejected that they represent Islam.
Baghdad's efforts to counter
This year's holy day was marred by a suspected suicide attack targetting Shi'ites in Jacobabad, Pakistan, which killed at least 24 people, according to a local minister.