South Sudan, currently part of Sudan - the largest country in Africa, is holding a historic referendum this week following a 2005 peace treaty, where its citizens will decide whether to remain unified, or for South Sudan to secede and become a new nation. The 2005 treaty brought to an end decades of civil war between the Islamic north and predominantly Christian and animist south. The south is expected to vote by around 99 percent to secede from the north - which will also give it a majority of Sudan's oil. Sudan's President Omar al-Beshir has stated he would honor the vote, whatever the outcome. Should the vote to secede pass, the hard work of defining borders, working out how to share oil revenue and more will have just begun. Collected here are images of Sudanese people participating in this week's vote. ( 35 photos total