Over the past three years, more than 100,000 Syrians have lost their lives in the escalating conflict between forces loyal to President Bashar al-Assad and those opposed to his rule. The bloody internal conflict has destroyed whole neighbourhoods and forced more than nine million people from their homes.This is the story of the civil war so far, in eight short chapters.ProtestsThe conflict has its roots in protests that erupted in March 2011 in the southern city of Deraa after the arrest and torture of some teenagers who painted revolutionary slogans on a school wall.When security forces opened fire on demonstrators, killing several, more took to the streets. The unrest triggered nationwide protests demanding President Assad's resignation.The government use of military force to crush the dissent merely hardened the protesters' resolve. By July 2011, hundreds of thousands were taking to the streets in towns and cities across the country.More: Protest footage from June 2011 mappedViolenceOpposition supporters eventually began to take up arms, first to defend themselves and later to expel security forces from their local areas.The country descended into civil war as rebel brigades battled government forces for control of cities, towns and the countryside. Fighting reached the capital Damascus and second city of Aleppo in 2012.In July 2013, the UN said more than 100,000 people had been killed. It has stopped updating the death toll, but activists say it now exceeds 140,000.The opposition remains fractious and deeply divided, unable to agree much apart from the need to end President Assad's rule.On the political front, alliances have been formed to gain international recognition. But they have been weakened by power struggles, a lack of support from grassroots activists and rebels, and limited financial and military assistance.The armed rebellion has evolved significantly, with as many as 1,000 groups commanding an estimated 100,000 fighters. Secular moderates are outnumbered by hardline Islamists and jihadists linked to al-Qaeda, whose brutal tactics have caused widespread concern and triggered rebel infighting.A UN commission of inquiry has been investigating all alleged violations of international human rights law since March 2011. It has evidence showing that both sides have committed war crimes including torture, hostage-taking, murder, execution and attacking protected objects.Although investigators have been denied entry into Syria and their communications with witnesses have been restricted, they have confirmed at least 27 incidents of intentional mass killings.They believe 17 were perpetrated by government forces and pro-government militia, including the incidents that left hundreds of civilians dead in Houla in May 2012 and Baniyas in August 2013. Rebel groups have meanwhile been blamed for 10 massacres, including the slaughter of at least 190 people in the Latakia countryside in August 2013 by jihadist and hardline Islamist fighters.Chemical weaponsBefore the uprising began, the Syrian military had one of the world's largest stockpiles of chemical weapons, comprising more than 1,000 tonnes of precursor chemicals and chemical agents, including sulphur mustard and sarin.The government insisted the toxic arsenal was secure and would never be used "inside Syria", but reports of chemical attacks began to surface in early 2013.Then on 21 August 2013, rockets filled with sarin were fired at several suburbs in the Ghouta agricultural belt around Damascus, killing between 300 and 1,430 people. The opposition and Western powers said it could only have been carried out by the government. President Assad blamed rebels for the deaths, but within weeks he agreed to a US and Russian deal that is hoped will see the removal and destruction of Syria's chemical weapons by the end of June 2013.RefugeesIn one of the largest refugee exoduses in recent history, more than 2.5 million people have fled Syria since the start of the conflict, most of them women and children. Neighbouring countries have borne the brunt of the refugee crisis, with Lebanon, Jordan and Turkey struggling to accommodate the flood of new arrivals. The exodus has accelerated dramatically since the start of 2013, as conditions in Syria have deteriorated drastically.A further 6.5 million people are believed to be internally displaced within Syria, many of them without access to aid, bringing the total number forced to flee their homes to more than 9 million - half of the population.The UN has asked for $6.5bn (£3.9bn) - its largest ever appeal - to provide medical care, food, water and shelter for the nearly three-quarters of Syrians expected to be in need of assistance in 2014.What began as another Arab Spring uprising against an autocratic ruler has mushroomed into a brutal proxy war that has drawn in regional and world powers.Iran and Russia have propped up the Alawite-led government of President Assad and gradually increased their support, providing it with an edge that has helped it make significant gains against the rebels in the past year. The Sunni-dominated opposition has meanwhile enjoyed varying degrees of support from its main backers - Turkey, Saudi Arabia, Qatar and other Arab states along with the US, UK and France.Lebanon's Shia Islamist Hezbollah movement and al-Qaeda-linked jihadist groups are also on the ground, supporting opposing sides and contributing to the steady rise of sectarianism.Peace talksWith neither side able to inflict a decisive defeat on the other, the international community long ago concluded that only a political solution could end to the conflict in Syria. However, a number of attempts by the Arab League and the UN to broker ceasefires and start dialogue have failed.Then, in May 2013, the US and Russia began work to convene a conference in Switzerland to implement the 2012 Geneva Communique, a UN-backed international agreement that calls for the establishment of a transitional governing body in Syria formed on the basis of mutual consent.The talks, which became known as Geneva II, did not begin until January 2014. They broke down the following month after only two rounds. The UN special envoy Lakhdar Brahimi blamed the Syrian government's refusal to discuss opposition demands and its insistence on a focus on fighting "terrorists" - a term Damascus uses to dismiss all opponents of Mr Assad.(BBC)ANN.Az