memorial museum's center for the prevention of genocide, newshour weekend special correspondent simona foltyn and journalist jason patinkin traveled to uganda to meet those refugees. >> reporter: civil war is emptying huge swaths of south sudan. the violence has uprooted four million people, including two million who've fled to neighboring countries. in the last year, more than a million south sudanese have poured into northern uganda alone, crossing makeshift bridges like this one to flee fighting, hunger, and brutal attacks on civilians. >> ( translated ): they started fighting very, very severely. so that made us to escape with our properties to this side. >> reporter: when seme lupai's family went to one of the refugee camps, initially, he stayed behind to look after the family's most precious commodity-- their cattle. he hid for a year to escape the violence. the refugees carry whatever they can salvage-- mattresses, pots, clothes, notebooks-- remnants of once peaceful lives turned upside down. at checkpoints, ugandan soldiers search their belongings for weapons, before the refugees proc

newshour weekend special correspondent simona foltyn and journalist jason patinkin made the treacherousjourney into to south sudan. >> reporter: in the hills of northeastern uganda, a concealed forest path leads across the border into south sudan. the young nation, mired in a four-year civil war, is increasingly difficult for journalists to access, so we use this hidden route to enter into rebel-held parts of the country. >> this is the river. >> reporter: we are traveling with martin abucha, a commander with a rebel group called the sudan people's liberation army in opposition. what separates abucha from other combatants in this war is, he's a dual south sudanese and american citizen with family in the united states. >> i would like to enjoy eating hamburgers. i'd like to enjoy going to burger king and mcdonald's with my daughters, and things like that. but i feel it's an obligation that i must carry. i don't want my kids to go through this. >> reporter: as we pass the peak of this hill, we cross into south sudan and meet the rebels. for the next four days, we'll travel with abucha to