Frenzied crowds went wild in Juba as South Sudan, the world's newest country, marked its long-awaited day of independence from the north when the clock struck midnight (2100 GMT Friday).
Fireworks lit the sky and packed cars drove around the city with drivers honking and passengers waving their new flag from the windows.
The noise from the large crowd gathered around countdown clock, at the main crossroads in the new country's capital Juba, was deafening, an AFP reporter said.
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Standing next to the flashing clock, which read "free at last," 27-year-old university student Andrew Nuer could barely describe how he felt as cars hooted around him and people danced in the street.
"We have struggled for so many years and this is our day -- you cannot imagine how good it feels," said Nuer, who had just come back from Cairo to celebrate independence.
"We pray to God in the future to help us make this a prosperous and peaceful country, and to show the world that we can do it," he added.
Hours earlier, world leaders including UN chief Ban Ki-moon had flown into Juba for Saturday's official celebrations.
"Fifty years fighting for independence and if this is freedom, then this is great," said Daniel Bol, banging his tin drum.
One sign on the back of a car full of flag waving southerners read: "Just divorced."
South Sudan's independence comes exactly six months after a referendum that saw southerners vote almost unanimously to split with their former civil war enemies in the north.
For decades, until a peace agreement was signed in 2005, southern rebels fought two wars with successive Khartoum governments for greater autonomy and recognition, a conflict that left the south in ruins and millions of people dead.
"We are free! We are free! Goodbye north, hello happiness!" screamed Mary Okach.
Saturday's independence ceremony is to be held at the mausoleum of the late rebel leader John Garang, who died only months after signing the peace accord that ended Africa's longest-running conflict and opened the door to eventual nationhood.
Military parades, prayers and a performance of the new national anthem are to take place from 0815 GMT, followed by the declaration of independence, the raising of the Republic of South Sudan's flag and the new country's first president, Salva Kiir, taking the oath of office.
The UN chief said after arriving in Juba on Friday that the people of the world's newest nation had "achieved their dream."
"The UN and the international community will continue to stand by South Sudan. I am very happy to be here," Ban added.
Watch SBS One on Sunday at 8.30pm, as Dateline's Yalda Hakim broadcasts from South Sudan.
