(NYT) – The swamp is so large it can be seen from space. During the rainy season, it stretches over an area the size of France, a forbidding maze of reeds and crocodiles that long warded off even the most intrepid of explorers searching for the source of the Nile, whose waters flood these clay plains. At night, swarms of ferocious mosquitoes seek out flesh. There are also tsetse and razor flies, and a variety of deadly snakes, not to mention the stifling humidity. This vast marshland, known as the Sudd, is also home to something else: tens of thousands of desperate civilians who have fled South Sudan’s civil war, the subject of a New York Times virtual reality film about children, resilience and survival.