With the civil war in Syria now more than two years old, the United Nations has made its biggest appeal ever for humanitarian aid - $5 billion.
The UN estimates more than 10 million Syrians - half the population - will need help by the end of the year - with up to four million children in need right now.
For the first half of this year, the UN called on governments to donate $1.5 billion - most of which is now committed.
But the UN says it needs more because the war has reached new levels of brutality - with one in three Syrians now in need of urgent aid.
"Between January and April, the number of people displaced in Syria more than doubled. These are massive figures, but those figures mask a human tragedy," said Valerie Amos, UN Emergency Relief Co-ordinator.
Currently, more than 1.5 million Syrians have left the country as refugees. The UN expects that number to jump to 3.5 million by the end of the year.
Every day, up to 7,000 new refugees are showing up at camps in other countries - which are already overcrowded and often unsanitary.
The UN says many of those still in Syria have had family members killed and are living without food, shelter, medical care and schooling.
The $5 billion the UN is seeking would cover people's most basic needs until the end of the year - that's it.
Aid workers say that, even if the fighting were to stop right away, people will need years to recover.
On Tuesday, the UN said there's new evidence of suspected massacres in Syria, rape being used as a weapon, and children's rights being violated.
It said some children have been killed in fighting, while others have been kidnapped, forced to watch torture, and in at least one case, take part in a beheading.
The UN also said there are "reasonable grounds" to believe chemical weapons have been used and it accused both sides of abuses. However, it said rebel acts did not "reach the intensity and scale" of those carried out by government forces.
It's believed 80,000 people have been killed since the war started.
UN investigators aren't allowed into Syria, so their report is based on first hand accounts from witnesses.
Meantime, the World Health Organization is warning about the risk of disease as summer gets closer.
According to the WHO, at least 35% of Syria's public hospitals are closed, and in some areas, up to 70% of the health workforce has left.
Because of that, Dr. Jaouad Mahjour of the WHO says "We are anticipating a number of public health risks from water-borne diseases, specifically hepatitis, typhoid, cholera and dysentery."
"Given the scale of population movement both inside Syria and across borders, together with deteriorating environmental health conditions, outbreaks are inevitable."
To get an even more personal account of the war, check out this piece by the BBC's Lyse Doucet, entitled 'Qusair - the Syrian city that died' (pictured below).
Doucet, the first western journalist to get into Qusair after it fell, opens her story with this...
"There is a maxim that's often been invoked in war - to save a city, you have to destroy it. That has been the fate of Qusair. Before it was plunged into battle some 18 months ago, it was a thriving border city of 30,000 set in lush groves of olives and apricots. Now, local officials tell us, only about 500 people still live in a place that lies in utter ruin."
via the Guardian