The streets of Cairo are brimming with campaign banners for the incumbent Abdel Fattah al-Sisi as Egypt gears up for a presidential election. Sisi is certain to win a third term in office despite rising public discontent amid the country's worst-ever economic crisis. From Sunday through Tuesday, Egyptians aged 18 and above will be able to cast their ballots for one of four candidates -- former army chief Sisi, in power since he deposed elected Islamist president Mohamed Morsi in 2013, and three other relative unknowns.