Lake Pukaki

Lake Pukaki is the largest of three roughly parallel alpine lakes running north–south along the northern edge of the Mackenzie Basin on New Zealand's South Island. The others are Lakes Tekapo and Ohau. All three lakes were formed when the terminal moraines of receding glaciers blocked their respective valleys, forming moraine-dammed lakes. The Alps2Ocean mountain bike trail follows the edge of Lake Pukaki for part of its length.

Source: Wikipedia