At 4am on Saturday, people in Damascus and Homs awoke suddenly to the sound of "World War III", as one local journalist described it.
The United States, with allies France and the United Kingdom, were in the midst of launching 105 cruise missiles at sites suspected of holding chemical weapons.
As the missiles lit up the city in Syria, halfway across the world, President Donald Trump held a press conference.
Mr Trump told media a strike targeting the use of chemical weapons was underway. He said he was "prepared to sustain this response until the Syrian regime stops its use of prohibited chemical agents."
The war in Syria is repeated described as "messy" and "complicated" - and it is.
Here we attempt to explain it.
Why did Donald Trump order the attack?
On April 7, civilians in Syria were attacked with chemical weapons.
The images that came out of the attack were horrifying - civilians convulsing and struggling for breath, children ash-faced and terrified. At least 42 people were killed.
The White House says "with confidence" it was the Syrian regime who used chemical weapons against civilians in that attack.
Barack Obama described chemical weapons as a "red line", and Mr Trump takes a similar stance, characterising their use as a step too far.
But Russia's Foreign Minister Sergei Lavrov says he has "irrefutable evidence" the attack was staged by foreign agents.
It is the second time Mr Trump has ordered retaliation after the Syrian government used chemical weapons.
In 2017 Mr Trump ordered the launch of 57 Tomahawk missiles from a boat in the Mediterranean Sea, targeting an airbase controlled by the Syrian government.
Mr Trump said that attack was also a direct punishment for Assad's alleged use of chemical weapons. It followed a horrific chemical weapons attack in Khan Sheikhoun which left 80 people reported dead, including, again, children.
Wasn't the US already fighting in Syria?
While the US has been fighting in Syria, it's been careful to avoid directly taking on the Assad forces.
Its fight in Syria has been against ISIS. There are currently about 2000 troops there.
The US threw its support behind Kurdish militia, who were also fighting ISIS. American airstrikes helped Kurdish forces halt the ISIS siege of Kobane and allowed the Kurdish militia to launch a counterstrike against ISIS in northern central Syria.
How did the war in Syria begin?
In 2011, protests broke out across Syria. Similar protests were taking place across the Middle East and northern Africa, grouped together as the Arab Spring. There were localised issues, but a common theme across the protests was a desire for democratic reform.
The Syrian government struck protesters violently and swiftly.
Members of the government's military, not wanting to fight against its own people, defected, banding together with protesters to form the Free Syrian Army.
By 2012, Syria was in full-blown civil war - the regime against the rebels.
The UN estimates 400,000 people have died in the conflict.
It's a civil war, but also a proxy war between Iran and the Gulf States
Syria has an historic alliance with Iran, which uses its territory to move weapons through to militias across the Middle East.
So when Syria entered war, the Gulf States and Egypt saw an opportunity to dislodge an Iranian ally. Since 2013 the Arab League has been arming the opposition forces in Syria.
Equally, Iran moved to back up its ally - the Syrian regime.
Why is Russia fighting in Syria?
The Assad government is a key ally for Russia and has been since the Cold War, when Syria allied with the USSR.
Russia has a naval base on Syria's coast - a warm water port on the Mediterranean Sea.
Russia entered the war in 2015.
Meanwhile, Russia has used its seat at the UN to veto Security Council proposals, and has backed up the regime's claims no chemical weapons were used. Russian officials have even suggested the attack was staged.
Then there are the terrorist groups.
Various jihadist militias have been fighting in Syria since the civil war escalated.
Al-Qaeda's Jabhat al-Nusra allied with some moderate rebels and became an effective anti-Assad force.
Then ISIS took advantage of the chaos caused by war and attempted to take hold.
As a result, the US backed Kurdish forces and sent in 2000 troops.
What about New Zealand?
Following the missile attack on chemical weapons, Prime Minister Jacinda Ardern neither explicitly supported nor condemned the show of force.
A statement said she "accepts" but does not necessarily support the attack.
Before forming the Government, the Labour Party campaigned on doubling the refugee quota from 750 to 1500 refugees a year, over a three year period. The promise was in part a response to the war in Syria.
We will find out after the Budget when an increase to the refugee quota will come into effect and how it will be rolled out.