(CNN)It is difficult to know at what point things of horror become forgotten and slip out of the world's view. Perhaps it is when they are eclipsed by another, seemingly more pressing crisis. Or when it becomes almost impossible -- for safety or other reasons -- for outside observers to bear witness to their daily toll. Aleppo has, somehow, sometime between late 2012 when it was the open sore of the Syrian civil war, and today -- when the fight against ISIS has completely grabbed the world's attention span -- slipped off the radar screen. But here is why it must not: there remain an estimated 300,000 civilians there, in rebel-held areas alone.
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An estimated 300,000 civilians are stuck in rebel-held areas around Aleppo
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They are at risk of barrel bombs and warring militias and are short of food, water and fuel
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Fierce battle under way for control of Handarat hill, on the road in to the rebel-held area
And as in so much of Syria's war, it has been that way for months and will probably go on so, as the outcome is so vital that nobody is prepared to give up: the fight for a small hill called @placeholder.