0121 GMT November 19, 2019
More than thirteen centuries ago, the Prophet Muhammad’s grandson Imam Hussein (PBUH), was martyred along with dozens of his companions during a last-stand battle against the tyrant of the time, Yazid I.
Imam Hussein is consequently a highly-venerated figure remembered not only among Shia Muslims but also among Sunnis and people of other faiths.
Starting since a few days before Arbaeen, the largest annual public gathering in the world, hundreds of different religious mourning processions, usually representing different communities and tribes of pilgrims from Iraq and around the world, passed by the golden-domed shrines of Imam Hussein and his half-brother Abbas ibn Ali (PBUH).
In a symbolic gesture honoring Imam Hussein, pilgrims streamed toward Karbala on foot from the cities of Najaf, 70 kilometers away, Baghdad, 90 kilometers (55 miles) to the north, and other places farther afield.
The pilgrims are greeted by the generous hospitality of the Iraqi people, who provide them with food, water, transport and accommodation needed for the journey.
Arbaeen – Arabic for the number forty – draws far more pilgrims than the Hajj in Saudi Arabia, a pilgrimage required once in a lifetime of every Muslim who can afford it and is physically able to make it.
The Arbaeen walk to Karbala has been a longtime tradition among Shia Muslims, which was largely abandoned after being prohibited during the despotic rule of deposed Iraqi dictator Saddam Hussein.
In neighboring Shia-majority Iran, Arbaeen is a national holiday.
Religious processions and symbolic marches were also held across different cities in Iran on Saturday.
In one of the symbolic processions, 3,000 university students mourned Arbaeen at the University of Tehran before walking on foot toward the Imam Khomeini Hussaniya in downtown Tehran to meet with Leader of Iran's Islamic Revolution Ayatollah Seyyed Ali Khamenei and join him in mourning the day.
In a brief address to the meeting, the Leader warned that the global arrogance and hegemonic powers are using their numerous propaganda machines to portray evil as good and evil as good.
Iran’s Deputy Interior Minister, Hossein Zolfaghari said that more than 3.4 million Iranians traveled to Iraq to attend the event. He added that 2 million of them have returned home.
Up until six years ago, only a maximum number of 35,000 Iranian pilgrims were reported to have taken part in any year during the event, marking a stark contrast with recent participation levels.
Participation numbers from other countries have also increased in recent years, with tens of thousands entering Iraq notably from countries such as Pakistan, Afghanistan, Azerbaijan, Turkey and Lebanon.
Press TV and AP contributed to this story.