(CNN)Here's a look at South Sudan, a landlocked country in east-central Africa, bordering Sudan, Ethiopia, Kenya, Uganda, Democratic Republic of the Congo and the Central African Republic. In 2011, South Sudan became the world's newest country after gaining its independence from Sudan.
About South Sudan:
(from the CIA World Factbook)
Area: 644,329 sq km, slightly smaller than Texas
Population: 12,042,910 (July 2015 estimate)
Median age: 17 years
Ethnic Groups: Dinka 35.8%, Nuer 15.6%, Shilluk, Azande, Bari, Kakwa, Kuku, Murle, Mandari, Didinga, Ndogo, Bviri, Lndi, Anuak, Bongo, Lango, Dungotona, Acholi (2011 est.)
Religion: Animist, Christian
GDP (purchasing power parity): $23.5 billion (2014 est.)
GDP per capita: $2,100 (2014 est.)
The country is poverty-stricken despite containing the majority of known Sudanese oil reserves.
A demilitarized, jointly monitored Common Border Zone has been established between Sudan and South Sudan to ease tensions regarding the oil-rich Abyei region.
March 27, 1972 - The signing of the Addis Ababa Agreement ends 16 years of civil war between the northern Khartoum forces and southern Anyanya rebels. Part of the agreement includes the creation of the autonomous region of South Sudan, with Juba as its capital.
1977 - Oil is discovered in southwestern Sudan. Civil war in the 1980s and 1990s prevents much exploration or development of the oil deposits.
1980s - Prolonged droughts put pressure on water and farming resources.
May 1983 - Col. John Garang de Mabior forms the Sudan People's Liberation Army (SPLA) and leads his forces against the government, re-igniting the civil war. The South is fighting against the government's proposal to re-divide the region and the imposition of an Islamic law and militaristic rule.
March 27, 1995 - Sudan's government calls for a two month cease-fire at the behest of former U.S. President Jimmy Carter.
July 15, 1998-May 1999 - The SPLA calls a three-month cease-fire due to regional famine, allowing U.N. supplies to reach famine victims. The cease-fire is extended until government bombs attack two cities in the South.
January 9, 2005 - The Comprehensive Peace Agreement is signed by representatives from the North and the South. Part of the agreement includes independence for southern Sudan within six years and that Islamic law would not apply there.
April 11-15, 2010 - Sudan holds multi-party elections for the first time in 24 years. Salva Kiir Mayardit is elected president of southern Sudan with 93% of the vote.
January 9-15, 2011 - Sudanese people vote in a referendum to secede or remain part of a unified Sudan. Sudanese nationals in the South, North, and in several foreign countries, including Australia, Canada, Egypt, Ethiopia, Kenya, Uganda, and the United States cast votes.
February 7, 2011 - The Southern Sudan Referendum Commission announces that 98.83% have voted for separation from the North. U.S. President Barack Obama declares Washington's intention to recognize South Sudan as an independent state in July, when the Comprehensive Peace Agreement is scheduled to end.
March 2011 - Violence breaks out in southern Sudan between soldiers and rebel groups.
April 27, 2011 - In a speech on state television, President Omar al-Bashir claims the disputed oil-rich region of Abyei on behalf of the North.
May 31, 2011 - The African Union announces that Sudan and South Sudan have reached an agreement over Abyei, in which a demilitarized, jointly monitored Common Border Zone is established.
June 5, 2011 - Fighting between the northern Sudanese Armed Forces and the Sudan People's Liberation Army of southern Sudan erupts near Kadugli, the capital of oil-rich Southern Kordofan state. The United Nations also reports violence in neighboring Blue Nile and Unity states.
June 15, 2011 - The United Nations says that 102,000 people have fled from the disputed region of Abyei.
June 20, 2011 - Representatives from Sudan and South Sudan sign an agreement calling for the immediate withdrawal of Sudanese troops from Abyei and for joint supervision of the disputed region.
July 14, 2011 - Becomes the 193rd member nation of the United Nations.
September 8, 2011 - According to U.N. officials, the governments of Sudan and South Sudan reach an agreement that will allow the withdrawal of their troops from the disputed border region of Abyei.
October 2011 - In his first visit to Khartoum since South Sudan's independence, President Salva Kiir meets with Sudanese President Omar al-Bashir to "reach final solutions" to address continuing differences between their countries.
January 23, 2012 - South Sudan shuts down oil production after accusing Sudan of stealing $815 million of its oil. Sudan says it confiscated the crude to make up for unpaid fees to use the pipeline and processing facilities in its territory.
February 10, 2012 - During talks mediated by the African Union, Sudan and South Sudan sign a nonaggression pact aimed at bringing peace to the border region.
April 12, 2012 - South Sudan forces claim the oil fields in the town of Heglig, which account for about half of Sudan's oil production.
April 20, 2012 - South Sudan announces the withdrawal of its troops from the contested, oil-rich area of Heglig. Sudan claims that the South Sudan troops were "forced to withdraw."
May 2012 - President Salva Kiir writes letters to more than 75 government officials and to eight foreign governments in an attempt to recover $4 billion lost to corruption. "If funds are returned, the government of the Republic of South Sudan will grant amnesty and keep your name confidential," writes Kiir in a letter sent to former and current "senior" officials.
May 30, 2012 - The U.N. peacekeeping mission confirms the full withdrawal of the Sudan Armed Forces from the disputed Abyei region but adds that Sudanese armed police forces remain in the area.
August 4, 2012 - African Union officials announce that negotiating teams from Sudan and South Sudan have agreed to end a dispute on oil payments to allow the resumption of southern oil exports through Sudan's territories.
September 27, 2012 - Sudanese President Omar al-Bashir and South Sudanese President Salva Kiir sign a deal to resume oil exports and establish a demilitarized zone and principles of border demarcation but do not reach a deal on the status of Abyei, a disputed region claimed by both countries.
March 8, 2013 - Defense ministers from Sudan and South Sudan sign an agreement to soon withdraw their respective military forces from the 14-mile-wide demilitarized zone between the countries.
December 15, 2013 - Deadly clashes begin, which President Salva Kiir later calls a failed coup attempt by soldiers loyal to sacked deputy Riek Machar. Days later, the Ministry of Foreign Affairs says 500 died and 800 were wounded in the fighting.
December 23, 2013 - The U.S. military's Africa Command announces it is positioning 150 Marines in Djibouti in East Africa to be able to respond should conditions in South Sudan deteriorate even more. On December 24, 50 of these Marines are moved closer, to Entebbe, Uganda, and on January 3, Marines evacuate about 20 U.S. Embassy staff members from Juba.
January 6, 2014 - Talks between South Sudan's government and rebels begin in Ethiopia, to resolve the three-week long violence that left more than 1,000 people dead and forced 200,000 from their homes.
January 11, 2014 - Between 200 and 300 women and children, fleeing violence in South Sudan, die when an overloaded ferry capsizes near Malakal.
January 23, 2014 - The South Sudanese government and rebels sign a cease-fire, which calls for an immediate end to all military operations and for the protection of civilians. The cease-fire agreement goes into effect on January 24.
February 18, 2014 - The U.N. peacekeeping mission in South Sudan (UNMISS) reports of renewed fighting in Malakal between pro- and anti-government forces, despite the cease-fire signed in January.
March 17, 2014 - Militants attack a U.N. peacekeepers' base in Bor, capital of the Jonglei state. At least 48 people are dead after the militants use rocket-propelled grenades to breach the base, where peacekeepers have been sheltering nearly 5,000 civilians.
February 21, 2015 - The United Nations says 89 children have been abducted form a South Sudanese School.
August 26, 2015 - Under threat of U.N. sanctions, President Salva Kiir signs a peace deal which rebel leader Riek Machar signed the previous week.
December 25, 2015 - South Sudan President Salva Kiir dissolves the country's 10 states and creates 28 new ones, state media reports. Rebels say the move is in violation of the treaty signed in August.
January 28, 2016 - Sudan's president orders the opening of the border with South Sudan for the first time since the South seceded five years ago, Sudan's state news agency reports.
January 29, 2016 - A report by the Joint Monitoring and Evaluation Commission to the African Union Peace and Security Council states that South Sudan government forces were responsible for the deaths by suffocation of 50 civilians in a container in October 2015. Implementation of the peace agreement "is lagging far behind schedule," according to the report.