Ruatapu Hydrothermal Cave
Ruatapu Cave (Sacred Cave) is situated in the Orakei Korako (the Place of Adorning) Hydrothermal Park - The Hidden Valley, on the shores of Lake Ohakuri, North Island, New Zealand. It is one of only two geothermally situated caves in the World and thought to have been formed by hydrothermal activity. At the bottom of the cave is the Pool of Mirrors (Waiwhakaata). The pool's acidity and chemnical composition give it the ability to clean jewellery!