Men grinning and waving, women singing and dancing, south Sudanese dressed in their finest queued by the thousand Sunday to vote in a landmark referendum expected to create the world's newest state.
They had begun forming up in orderly sex-segregated lines from soon after midnight, eager to be among the first to have their say on whether the impoverished south should finally break away from rule by Khartoum, ending five decades of conflict between north and south.
When the polls finally opened at 8:00 am (0500 GMT) for the start of the seven-day vote, the excitement was electric. Each time the next vote was inserted in the ballot box, women ululating in celebration.
A few voters wore their opinions on their chests with T-shirts demanding independence. Most donned the Western suits and brightly coloured floral dresses normally reserved for church in this largely Christian region but they showed no less enthusiasm for separation from the Muslim, mainly Arab north.
The deputy head of the organising committee, Chan Reec, was effusive about the massive turnout in the first hours of the independence vote. "There is singing, there is dancing, this is a day like no other in the history of the people of south Sudan," he told AFP.
The independence referendum is a key plank of the 2005 north-south peace deal that ended a devastating 22-year civil war in which some two million people were killed and another four million displaced.
South Sudanese president Salva Kiir was among the first to cast his ballot in the regional capital Juba.
"This is the historic moment the people of south Sudan have been waiting for," Kiir said, holding up his hand to reporters to show the indelible ink that demonstrated he had voted.
US envoys Scott Gration and John Kerry as well as Hollywood star George Clooney watched as he cast his ballot at a polling station set up at the memorial to late rebel leader John Garang in the regional capital Juba.
It was Garang who signed the 2005 peace agreement that provided for Sunday's referendum, shortly before his death in a mysterious helicopter crash on his way back from Uganda.
His widow Rebecca said: "I have mixed feelings about this day for I know that my husband did not die in vain and I know that freedom has a price," she said.
Southern leaders had urged voters to come out en masse on the first day. The 2005 peace deal requires a turnout of at least 60 percent for the referendum to be valid. The outcome will then be decided by simple majority.
Some 3.75 million people are registered to vote in the south and around 117,000 in north Sudan, the majority of them in capital Khartoum.
Yar Mayon, who grew up in refugee camps in Ethiopia and Kenya, said: "I came here in the early morning because I wanted to show just how much I wanted to vote."
As the sun rose, another voter, Wilson Santino said: "This is a new dawn because we vote for our freedom."
After touring a polling station with ex-US president Jimmy Carter, former UN chief Kofi Annan said: "It is important that the energy and enthusiasm lead to solid results that are accepted by everybody."
Carter, who held talks with northern leaders in Khartoum before heading to Juba for the vote, said he believed the prospects for the referendum to result in new violence had greatly receded in recent days.
"Now there is a general acceptance in the north and south that if a vote for independence should be cast -- and we don't know that yet -- then it will be accepted peacefully."
Sudanese President Omar al-Bashir, an army man who led the north's war effort against the south for a decade and a half before signing the 2005 peace deal, has said he will respect the outcome of the vote if it is "free and transparent."
But many ordinary people in the north were less accommodating.
"If you want to come back, you will first have to apply for a visa," scoffed Hamdi Mahmoud Hassan, when told by a southern fellow police officer that he had voted for secession, one of the few to do so in the north, where -- in stark contrast to the south-- turnout amounted to no more than a trickle.
Hassan said he was "furious" but also resigned to the prospect of the partition of Africa's largest nation.
The run-up to polling day had been overshadowed by deadly clashes in two remote oil-producing districts on the north-south border that were bitterly contested in the most recent, 1983-2005 round of conflict but a military spokesman said the situation was calm across the south on Sunday.
Results are not expected until early next month because of the immense logistical problems involved in collecting ballot boxes in a vast, war-ravaged region which has just 40 kilometres (25 miles) of tarmac road, most of it in Juba.