The Wai-O-Tapu Scenic Reserve - Thermal Wonderland - part of the Maroa Caldera formed 160,000 years ago, the largest area of surface thermal activity of any system within the Taupo Volcanic Zone. Natural compounds rising to the surface include iron oxide, manganese oxide, sulfur, mercury sulfide, arsenic, antimony, gold, silver and in some cases, unrefined crude oil, which was collected and burned in lanterns. Near Rotorua on the North Island of New Zealand. The last photos are of the Te Manaroa Spring, literally a creek of naturally boiling water winding its way through a jungle. In the last photo, large bubbles of gas were rising into a natural spring pool.