New Zealand is the top of a continent. Around it lies Zealandia, close to five million square kilometres of continental crust, granite and old sediments and all, that broke away from Gondwana some eighty million years ago, was stretched thin, and sank. About ninety-four per cent of it is under the sea; New Zealand and New Caledonia are most of what shows. Geologists made the case for calling it a continent in 2017, and the argument was mostly about the reference point. Measured from sea level it is a scattering of islands. Measured from the ocean floor around it, it stands up clear and distinct, the way continents do, only with the water reaching higher up its sides. Nothing about the rock changed when it was named. Someone just stopped counting from the surface.