Volcanic lake near the summit of Mount Tongariro, New Zealand. The bright colours of the lake are from minerals dissolving at the high pressures and temperatures inside the volcano. Immediately behind the lake is the summit crater of Tongariro (1968 metres). Behind that, is the summit of Mount Ngauruhoe (2291 metres). The cloud seen at left of Ngauruhoe is obscuring the summit of Mount Ruapehu (2796 metres). The Tongariro and Ngauruhoe peaks are actually considered to be part of the same volcano. These three volcanic peaks are part of Tongariro National Park on the North Island of New Zealand. Volcanic activity started some 2 million years ago, and the volcanoes are still active.