Lake Pukaki is a flat expanse of opaque turquoise in the Mackenzie basin of New Zealand's South Island, and the colour is rock. The Tasman River arrives loaded with flour that the Tasman and Hooker glaciers have ground to dust. Those particles hang near the surface, throwing blue and green back while the reds are absorbed. Down at the shingle the whole thing gives itself away. A handful of water that reads as opaque paint from the lookout is almost clear in your palm, a little grey silt in the creases. The colour lives in the depth, in dust too fine ever to settle out. The lake was dammed long before any engineer arrived. The glacier that once filled this whole valley dumped its load in ridges across the mouth, and the modern dams only raised what the ice had already made.
From the highway lookout at the northern end, Aoraki lines up head-on down the axis of the valley, the highest ground in the country at 3,724 metres. State Highway 80 then runs fifty-odd kilometres up the western shore with the colour on your right the whole way. The mountain grows in your windscreen until the tawny tussock runs straight into the snow wall of the Alps. For a few weeks from late November the eastern arm and the road verges erupt purple and pink with Russell lupins. They are the picture that made the Mackenzie famous. They are also a problem: garden plants gone wild, smothering the bare gravel where the kakī, the black stilt, has to nest. At night this is a gold-tier dark-sky reserve, and the bright centre of the galaxy stands high over you rather than low on the horizon. In Ngāi Tahu tradition Aoraki is not a mountain but an ancestor, a boy from the sky whose canoe struck a reef and turned to stone.