A chasm and a crack on the Brunt Ice Shelf in Antarctica are creeping closer and closer to one another, and when the two finally meet, a slab of ice twice the size of New York City will break away and float out to sea. The two glacial flaws are about 4km apart, and it could take days or months for them to finally rendezvous. But when they do, the iceberg that forms in the Weddell Sea will not be the largest to orbit Antarctica. In fact, it might not even make the historical top 20.