Hundreds of thousands of Shiite Muslims walked, rode bikes and drove cars to this holy city on Sunday for religious rituals once banned by Saddam Hussein.
Men, women and children beat their chests and chanted prayers in unison in a ceremony marking Ashoura, the most important in the Shiite Muslim calendar. The 10-day festival commemorates the death of Shiite saint Imam Hussein, a grandson of the prophet Muhammad.
Imam Hussein, killed in a power struggle in 680, is buried in a gold-domed shrine in Karbala. His death was part of a dispute over leadership of the faith. It was also a key event in Islam's split into the Sunni and Shiite branches.
This is the first time in more than three decades that Iraq's Shiites have been free to publicly celebrate the holiday.
"We have been waiting for this ceremony for 30 years. I can't begin to describe my feelings. This is total freedom," said Saad al-Masoudi, a 40-year-old resident of Karbala, as he walked in a colorful procession.
Under Saddam's Sunni-dominated regime, Shiite celebrations were tightly controlled, and self-flagellation, was banned.
"This is a blessing from God. I have been coming here for more than 20 years. The difference between now and last year is the same as the difference between the Earth and the sky," said Abed Hasan Hussein al-Ataby, a 74-year-old man from Baghdad.
Next to the shrine, boys as young as six years beat their backs with chains in a show of remorse for Imam Hussein's death.
Behind them, rows of men pounded their chests in unison.
The ceremony culminates on Tuesday, when more than 2 million people, including at least 100,000 Iranians, are expected to gather in the city.
"Finally I'm here. After years of preventing us from coming, he (Saddam) is gone and we are free to visit and pray," said Anwar Sabah Jaafar, 21, of Isfahan, Iran.
Security forces and rival Shiite militias, kept a close eye on proceedings. Authorities fear extremist might attack to raise tensions between Iraq's Shiite majority and Sunni minority.
Police and Polish soldiers set up checkpoints on roads leading up to Karbala, searching cars and pedestrians and setting up a 12-mile cordon, preventing most cars from entering the city.
The ceremony comes at a time when Shiite Muslim are vying for power in Iraq, after decades of persecution by Saddam.
The Shiites make up 60 percent of Iraq's 24 million people, and Shiite clerics have emerged as key centers of political powers, particularly Grand Ayatollah Ali al-Sistani.