Syria has been engulfed in a devastating civil war since 2011 after Syrian President Bashar Assad lost control over large parts of the country to multiple revolutionary groups. The conflict has since drawn in foreign powers and brought misery and death to Syrians.

Syria's army, officially known as the Syrian Arab Army (SAA), is loyal to Syrian President Bashar al-Assad and is fighting to restore the president's rule over the entire country. The SAA has been fighting alongside a number of pro-Assad militias such as the National Defense Force and has cooperated with military advisors from Russia and Iran, which back Assad.

Turkey, which is also part of the US-led coalition against IS, has actively supported rebels opposed to Assad. It has a tense relationship with its American allies over US cooperation with Kurdish fighters, who Ankara says are linked to the Kurdistan Workers' Party (PKK) fighting in Turkey. Turkey has launched multiple military offensives targeting Kurdish militias.

The Kremlin has proven to be a powerful friend to Assad. Russian air power and ground troops officially joined the fight in September 2015 after years of supplying the Syrian army. Moscow has come under fire from the international community for the high number of civilian casualties during its airstrikes. However, Russia's intervention turned the tide in war in favor of Assad.

A US-led coalition of more than 50 countries, including Germany, began targeting IS and other terrorist targets with airstrikes in late 2014. The anti-IS coalition has dealt major setbacks to the militant group. The US has more than a thousand special forces in the country backing the Syrian Democratic Forces.

The Free Syrian Army grew out of protests against the Assad regime that eventually turned violent. Along with other non-jihadist rebel groups, it seeks the ouster of President Assad and democratic elections. After suffering a number of defeats, many of its members defected to hardline militant groups. It garnered some support from the US and Turkey, but its strength has been greatly diminished.

Fighting between Syrian Kurds and Islamists has become its own conflict. The US-led coalition against the "Islamic State" has backed the Syrian Democratic Forces, an alliance of Kurdish and Arab militias. The Kurdish YPG militia is the main component of the SDF. The Kurds have had a tacit understanding with Assad.

"Islamic State" (IS) took advantage of regional chaos to capture vast swathes of territory in Iraq and Syria in 2014. Seeking to establish its own "caliphate," IS has become infamous for its fundamentalist brand of Islam and its mass atrocities. IS is on the brink of defeat after the US and Russia led separate military campaigns against the militant group.

IS is not the only terrorist group that has ravaged Syria. A number of jihadist militant groups are fighting in the conflict, warring against various rebel factions and the Assad regime. One of the main jihadist factions is Hay'at Tahrir al-Sham, which controls most of Idlib province and has ties with al-Qaeda.

Iran has supported Syria, its only Arab ally, for decades. Eager to maintain its ally, Tehran has provided Damascus with strategic assistance, military training and ground troops when the conflict emerged in 2011. The Iran-backed Lebanese Shiite militant group Hezbollah also supports the Assad regime, fighting alongside Iranian forces and paramilitary groups in the country.

In 2011, as regimes crumble across the region, tens of thousands of Syrians take to the streets to protest against corruption, high unemployment and soaring food prices. The Syrian government responds with live ammunition, claiming some 400 lives by May.

At the urging of Western countries, the UN Security Council condemns the violent crackdown. The EU and US implement an arms embargo, visa bans and asset freezes in the months that follow. With the backing of the Arab League, calls eventually grow for the Syrian president's departure. But not all UN members agree with this demand.

Bashar al-Assad - who has been in power since the death of his father in 2000 - sees his reputation wane with the continuing unrest. He refuses to end decades-long emergency rule, which allows for surveillance and interrogation. Russia backs its ally, supplying weapons and vetoing UN resolutions on Syria multiple times.

By the end of the year, human rights groups and the UN have evidence of human rights abuses. Civilians and military deserters are slowly beginning to organize themselves to fight back against government forces, which have been targeting dissidents. More than 5,000 have died so far in the fighting. It will take another six months before the UN acknowledges that a war is taking place on Syrian soil.

In September 2012, Iran confirms that it has fighters on the ground in Syria - a fact long denied by Damascus. The presence of allied troops underscores the hesitance of the US and other Western powers to intervene in the conflict. The US, stung by failed interventions in Afghanistan and Iraq, sees dialogue as the only reasonable solution.

As the death toll nears 100,000, the number of refugees in neighboring countries - such as Turkey and Jordan - hits one million. That number will double by September 2013. The West and the Arab League have seen all attempts at a transitional government fail in the two years of war, watching as fighting spills over into Turkey and Lebanon. They fear Assad will stay in power by any means possible.

Assad has long claimed he's combatting terrorists. But it's not until the second year of war that the fragmented Free Syrian Army is definitely known to include radical extremists. The group Al-Nusra Front pledges allegiance to al Qaeda, further splintering the opposition.

In June 2013, the White House says it has evidence that Assad has been using sarin nerve gas on civilians - a report later backed by the UN. The discovery pushes US President Barack Obama and other Western leaders toward considering the use of military force. However, Russia's proposal to remove the chemical weapons ultimately wins out.

Reports of a new jihadist group calling itself the Islamic State of Iraq and the Levant (ISIL) emerge in the final weeks of 2013. Taking land in northern Syria and Iraq, the group sparks infighting among the opposition, with some 500 dead by early 2014. The unexpected emergence of IS ultimately draws the US, France, Saudi Arabia and other nations into the war.