Who are the main humanitarian aid donors? How much has been given so far? Where is aid being spent, and on what?
As Syria's humanitarian crisis escalates, so do appeals for aid.
Last month, the UN revised upwards its requests for funding, announcing the largest emergency appeal in its history. Despite this, aid officials warn "money is going out as fast as it is coming in", and that the UN's multibillion-dollar requests still may not be enough in a crisis where demands frequently outstrip resources.