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We're starting the show in the African country of South Sudan. It's considered the newest or youngest nation on Earth. It's got its independence from Sudan in 2011 and it has struggled.

According to the U.S. Central Intelligence Agency, less than a third of South Sudan's population can read and write. Half the people there live below the poverty line.

Years of warfare and having to live their homes meant that many of South Sudan's adults missed out on school and some experts are saying that the nation's ethnic tensions are threatening to stir up genocide, the mass murder of a racial or a cultural group. Why?

Observers say militias based on people's ethnicity are arming up and squaring off. They say there's been an increase in hate speech. South Sudan's government has been accused of destroying villages and armed groups have reportedly been attacking civilians.

Hundreds of thousands of South Sudanese have fled to neighboring countries since 2013, and though tens of thousands of United Nations peacekeepers are in the country, they have still been repeated flare-ups of violence.

DAVID MCKENZIE, CNN CORRESPONDENT: Violence is raging in the world's newest country. Hundreds are feared dead in Juba, the capital of South Sudan. Many have fled the city. Others are hunkering down, trying to stay safe.

It looks like it could go from bad to worse.

But what exactly is going on?

Here is a breakdown.

SUBTITLE: South Sudan: How we got here.

South Sudan is a nation in East Africa and turned five years old earlier in July. The country broke away from Sudan in 2011 after decades of epic and political conflict. South Sudan's president is this man, Salva Kiir, and this is his long time rival and vice president, Riek Machar.

Civil war broke out in 2013 after the president accused the vice president of an attempted coup. Machar was sacked and forces loyal to each side began fighting.

The conflict also has a strong ethnic dimension. You see Kiir is a Dinka. That is the largest ethnic group in South Sudan. And Machar is a Nuer.

And traditionally, Dinka and Nuer are rivals in the country.

The war killed more than 50,000 people and displaced more than two million, about one in six people.

A peace deal signed last year meant Machar coming back to his post, which has only been in for a few months, and forces loyal to him have been stationed in Juba. And with heavily armed troops backing the rivals, it was almost inevitable that there will be a blowup.

Now the fear is, is that South Sudan, the youngest country on earth, will slide back to war and chaos, and civilians are often the worst hit.