By day Lake Tekapo glows an unreal milky-turquoise; by night it lies under some of the clearest skies in the Southern Hemisphere. The colour is not a trick of the light but of stone. Glaciers in the Southern Alps grind bedrock into an ultra-fine powder called rock flour, which stays suspended in the meltwater and scatters blue-green back at you. The lake sits at around 710 metres in the wide, dry Mackenzie Basin of the South Island. In 2012 the country around it became the Aoraki Mackenzie International Dark Sky Reserve, the largest in the Southern Hemisphere. On the shore stands the little Church of the Good Shepherd, built in 1935 from rough local stone as the first church in the basin. With snow-veined peaks behind it and turquoise water in front, it is one of New Zealand's most photographed buildings.
In late spring the lakeshore and roadsides erupt with purple, pink and blue lupins, and by day you can kayak the cold turquoise water or soak in hot pools above it. After dark the place changes character entirely. Guided tours climb Mount John, where the University of Canterbury runs New Zealand's main observatory and its largest telescope. On a clear, moonless night the Milky Way arcs from ridge to ridge, and the Southern Cross and the two Magellanic Clouds show plainly to the naked eye, doubled in the still water below. The lake now carries its dual name, Takapō, and stargazing tours run year-round by reservation. It is one of the rare places whose fame rests as much on its sky as on its shore.