The violence in Syria began in March 2011. The middle eastern country has been crippled by a brutal civil war.
Since then, the United Nations estimates more than 100,000 people have died in the clashes between President Bashar al-Assad's government and rebel forces who want him out.
The UN also says more than two million people have fled Syria to neighbouring countries, and over half of those refugees are children.
In July 2012, the International Red Cross said the violence in Syria had become so widespread that it was in a state of civil war.
But what are the reasons behind the violence? And what is being done to stop it getting any worse?
How did it all start?
The trouble began in 2011 in the Syrian city of Deraa.
Locals took to the streets to protest after 15 schoolchildren had been arrested - and reportedly tortured - for writing anti-government graffiti on a wall.
The protests were peaceful to begin with, calling for the kids' release, democracy and greater freedom for people in the country.
The government responded angrily, and on 18 March 2011, the army opened fire on protesters, killing four people.
The following day, they shot at mourners at the victims' funerals, killing another person.
People were shocked and angry at what had happened and soon the unrest had spread to other parts of the country.
What do the protesters want and what have they got?
At first the protesters just wanted democracy and greater freedom.
But once government forces opened fire on peaceful demonstrations, people demanded that the President, Bashar al-Assad, resign.
President Assad refused to step down.
As the violence worsened he offered to change some things about the way the country is run, but the protesters didn't believe him.
President Assad also has quite a lot of people in Syria that still support him and his government.
Who are the rebel fighters?
There isn't a clear single group of rebels, united against President Assad.
The opposition, who all want the president to step down, is split between groups of rebel fighters, political parties and people living in exile, who cannot return to the country.
The Free Syrian Army is the largest group fighting military battles against the government. It's far smaller than the government's army; it's poorly equipped and most of its fighters have only had basic training.
There are many smaller military groups all fighting against the government, but they are not under the control of the Free Syrian Army and some of them hold extreme views against western countries.
Other opposition groups try to distance themselves from the violence. Instead they claim to offer an alternative to the current government and propose a peaceful political solution to the crisis.
Chemical weapons
There has been increasing pressure on the international community to act after it emerged that chemical weapons are being used in the war.But in August 2013, a chemical attack just outside the Syrian capital, Damascus, caused a strong reaction from the likes of America, Britain and France.
After the effects of these weapons were seen, there were long discussions over what the rest of the world should do.
In September 2013, United Nations inspectors confirmed that chemical weapons had been used in Syria, but the report did not say who was responsible.
Syria, however, denies using chemical weapons, which are banned under international law because the effects of their use are so horrific.
The government said: "There is no country in the world that uses a weapon of ultimate destruction against its own people."
It blamed the rebel forces for the chemical attack.
Destruction of chemical weapons
The chemical attack caused international outrage and many leaders argued it demanded a strong response.
But MPs in Westminster voted against Britain being involved in military action in Syria.
The American and French governments discussed limited missile strikes against military targets in Syria.
But Russia has strong ties with President Assad's Syrian government and has helped Syria in the past by supplying weapons.
In September 2013 Russia suggested a solution that could avoid a wider conflict: that the Syrian government should give up its chemical weapons and commit to destroying them so they can never again be used.
The process of destroying the weapons began in October, and the people
The refugee crisis
Many ordinary Syrian people have been caught up in the violence of the war and have been forced to leave their homes to escape to other countries.
Every day refugees stream across the borders of Syria into the neighbouring nations of Jordan, Lebanon, Turkey and Iraq.
In August 2013 the United Nations said that the number of Syrian children who'd been forced to flee the country had reached one million.
Millions more have been displaced within Syria and are in desperate need of help. But aid agencies say that getting aid to people inside Syria is too difficult and dangerous.working on this project were awarded the Nobel Peace Prize later that month.
What happens next?
It doesn't look like the fighting is going to end any time soon.
There appears to be a stalemate between the two sides: the government forces are unable to defeat the rebel groups and vice versa.
The leading rebel group the Free Syrian Army has the support of the US, Britain and other European countries, but those countries say they cannot help the rebels by sending weapons because they don't want them to get into the wrong hands. There are some Syrian rebel groups that the US and Britain fear could be dangerous.
This is a subject of much debate as many people believe the Free Syrian Army need weapons to defend themselves and to fight for their cause.
In December 2013 the US and Britain stopped all 'non-lethal' supplies to the Syrian rebel groups too. Non-lethal supplies means things like medicine, vehicles and communication equipment.
The countries have continued to supply aid such as food and emergency supplies, but the US and Britain said they had to stop all other support as they feared the equipment would be stolen by rebel groups which they did not support.
For now, discussions continue between powerful nations like the US, Russia, Britain and France, to try to work out if there's another way to help Syria achieve peace.
