In New Zealand’s Nelson Lakes National Park, about 1,200 meters (4,000 feet) above sea level and a two-day hike from nearest civilization, lies Rotomairewhenua, or Blue Lake.

Tongariro national park view from Taupo the largest freshwater lake in New Zealand. (Image: Getty) One of the major eruptions of Taupō Volcano is the Oruanui Eruption, which occurred around ...