The iceberg that was for a time the biggest in the world is no more. A68, as it was known, covered an area of nearly 6,000 km²    1    it broke away from Antarctica in 2017. That's like a small country. But satellites show the mega-berg has now virtually gone, broken into countless small fragments    2    the US National Ice Center says are no longer worth tracking. Most glaciologists regard A68 as the product of a very    3    （nature）process, and it has nothing to do with human-induced climate change.