The civil war in Syria has been raging for over four years now and has shown no signs of abating.
An incredibly complex web of belligerents within the country is further muddied by the involvement of international actors.
The broad picture is one of western-backed rebel groups fighting an insurgency against the government forces of President Bashar al-Assad while trying to stem the growth of the so-called Islamic State (IS).
A harrowing report by HumanRights Watch also claimed government forces have been responsible for the detention and torture of hundreds of children.
Testimony from one child said: "Every so often they would open our cell door and yell at us and beat us. They said, 'You pigs, you want freedom?' They interrogated me by myself. They asked, 'Who is your god?' And I said, 'Allah.' Then they electrocuted me on my stomach, with a prod. I fell unconscious. When they interrogated me the second time, they beat me and electrocuted me again. The third time they had some pliers, and they pulled out my toenail. They said, 'Remember this saying, always keep it in mind: We take both kids and adults, and we kill them both.' I started to cry, and they returned me to the cell."
The war has created nearly 4 million refugees, many of who have fled to Europe.
In the image above made from video posted online by the Shaam News Network, a loosely organized group opposed to Bashar Assad, on Sunday, Aug. 16, 2015, which has been verified and is consistent with other AP reporting, shows the bodies of people killed in Syrian government airstrikes in Douma, a suburb of Damascus, Syria. The United Nations humanitarian chief said on Monday he is "horrified" by the attacks on civilians taking place in Syria, singling out in particular government airstrikes the previous day that killed nearly 100 people in a Damascus suburb.
Regular Regime Soldiers And Officers 52,077
The Syrian Armed Forces are the official military of Syria coordinated by the country’s beleaguered government. They consist of an army, navy, air and defence force and number around 220,000 regular servicemen and women.
The force has shrunk by close to half since civil war began in Syria in 2011, but it retains a flexibility which complements the guerrilla nature of battles and combat in the country.
Before the beginning of the Syrian civil war, mandated military service for men aged 18 was in decline. But since the Syrian government has re-focused its efforts on ensuring its young people serve in the armed forces.
In the photo above, Syrian soldiers carry a wounded comrade on a stretcher in Harasta, northeast of Damascus, Syria, Thursday, Oct. 22, 20115. Syrian troops have been fighting rebels in the frontline district, which lies on the northeastern edge of Damascus and only few kilometers (miles) from the presidential palace, since 2013. Neither side has been able to make a breakthrough in the fighting, although state media has reported Syrian army advances in the last week as part of a major army offensive.
YPG (Kurdish People's Protection Units), Rebel And Islamist Fighters 42,201
AP Photo/Lefteris Pitarakis)
The ongoing Syrian Kurdish-Islamist element began in parallel with the country’s civil war. The Kurdish People’s Protection Units (YPG) and Islamist rebel factions have fought over control of Islamist-controlled regions around Ras al-Ayn.
In the photo above, Syrian Kurdish fighter Delkhwaz Sheikh Ahmad, 22, sits with his sons, Dilyar, left, 3 and Ibrahim, 2, right, at his brother's house in Suruc, on the Turkey-Syria border, as he prepares to leave for Kobani, Syria, to rejoin the fighting, Friday, Oct. 17, 2014.
Sheikh Ahmad is a member of the Peoples Protection Units, also known as YPG and is fighting against militants of the Islamic State group in Kobani, Syria.
Every few weeks, he takes a couple of days to cross the border into Turkey to visit his family that had evacuated. Kobani, also known as Ayn Arab, and its surrounding areas, has been under assault by extremists of the Islamic State group since mid-September and is being defended by Kurdish fighters.
Islamic State And Other Islamist Factions 37,010
AP Photo/Mehmet Shakir, File
One of the most complicating factors in the conflict in Syria is the presence of Islamic State (IS), Al-Qaeda and the infighting between the rebel factions.
Despite all this - and muddying the picture even further - elements of IS have co-operated with the Al-Nusra Front to fight Hezbollah.
The battle for supremacy between jihadi groups in Syria has been incredibly damaging for the Syrian opposition and diminish the likelihood of a national or even provincial victory.
In the photo above taken on Saturday, April 18, 2015, a car passes in an area that was destroyed during the battle between the U.S. backed Kurdish forces and the Islamic State fighters, in Kobani, north Syria.
Nationalist Syrian Fighters 35,235
Assad's forces are supported by a number of nationalist groups, the largest of which is the Syrian Social Nationalist Party (SSNP).
This organisation and others such as the Arab Nationalist Guard and the Syrian Resistance espouse an ideology counter to the religious and sectarian lines that characterise many others in the conflict.
These fighters are not part of Syria's official army.
In the photo above, a Lebanese member the Syrian Social Nationalist Party carries her son with colors of the Syrian national flag is painted on his face, during a demonstration against a possible military strike in Syria, in front of the United Nations headquarters, in Beirut, Lebanon, Sunday, Sept. 8, 2013.
They are currently in control of the Idlib governorate in the north-west of Syria and are fighting IS as well as Assad's forces.
Despite receiving $123 million from the US in "non-lethal aid" in 2013, the group has been hampered by infighting and lost fighters who joined the better equipped and more motivated Al-Nusra Front. As the FSA's rebellion stalled that year, more and more fighters felt compelled to join this and other Islamist groups.
Currently the FSA is described as "a loose-knit association of groups" and has been subject to airstrikes from Russian jets.
The FSA have worked alongside the Syrian National Council (SNC) and the National Coalition for Syrian Revolutionary and Opposition Forces (NCSROF).
In the photo above, Syrian army defectors celebrate shortly after they defected and join the anti-Syrian regime protesters at Khaldiyeh area in Homs province, central Syria. Now four years later, the activistsâ goals are eclipsed in a conflict many believe has become a choice between rule by Assad and rule by Islamic radicals and they prefer the former.
Although they perform many social programmes including the running of hospitals, their armed paramilitary wing, the Jihad Council has carried out numerous attacks against the US, Israel and other Western interests.
This has lead to them being deemed a terrorist organisation by countries including the UK, US, France as well as the EU.
They fight in Syria on the side of President Bashar Assad, reportedly committing 2,000 fighters against rebels in the battle for Aleppo in June.
In the photo above, Hezbollah fighters carry the Hezbollah flag-draped coffins of Shiite fighters, who were killed in Syria supporting Syrian government forces, during a rally to mark the 13th day of the Shiite mourning period of Muharram, in Nabatiyeh, Lebanon, Tuesday, Oct. 27, 2015. Shiite Muslims observe Muharram, the first month in the Islamic calendar, as a month of remembrance and in particular they mark the death in the 7th century of Imam Hussein, a grandson of the Prophet Muhammad, at the Battle of Karbala in present-day Iraq.
Unidentified Dead 3,258
AP Photo/Hussein Malla, File
Unfortunately the horrors and scale of the conflict mean many of the dead have simply gone unidentified.
In this photo from 2012, a Free Syrian Army soldier, left, looks at dead bodies laying on a roadside in front of al-Shifa hospital, at al-Shaar neighborhood, in Aleppo city, Syria.
From the three-year-old boy who washed ashore on a Turkish beach to the 71 migrants who suffocated in a truck in Austria to the daily scenes of chaos unfolding in European cities as governments try to halt a human tide heading north.
There is no let up to the horrors that Syria's civil war keeps producing. Syria's brutal conflict, now in its fifth year, has touched off the greatest humanitarian crisis of our time.