Orakei Korako is a highly active geothermal area most notable for its series of fault-stepped sinter terraces, located in a valley north of Taupō on the banks of the Waikato River in the Taupō Volcanic Zone, New Zealand. It is also known as "The Hidden Valley". The New Zealand Ministry for Culture and Heritage gives a translation of "place of adornment near the white [sinter flat]" for . History of the region From earliest times the Waikato Valley near Orakei Korako was occupied by Māori of the Ngāti Tahu sub-tribe of Tuwharetoa. By the early 19th century the Māori population had congregated at Orakei Korako, probably attracted by the hot springs, which they used for cooking and bathing. Around 1819, the local Māori hid in an alum cave on the site from a passing raiding party of Ngapuhi and Ngati Paoa. The date when the Ngāti Tahu vacated the valley to settle at other locations is not recorded, but it has been suggested that they left after the eruption of Mount Tarawera in 1886, when great changes are alleged to have occurred in the hot springs. By the turn of the 20th century all but two families had moved from Orakei Korako. The earliest known route from Rotorua to Taupō for early European travellers passed right through Orakei Korako, and it was the existing Māori who provided a dugout canoe for the river crossings. It was at this point in the early 20th century that the geothermal area was established as a visitor attraction. To transfer visitors across the then-swift Waikato River they used the dugout canoe, until in the 1930s a wire-strop and pulley system was erected across the river, and a punt with a guiding rudder was used to catch the flow and propel the punt to the other side. The tourist resort was officially opened on 15 December 1937. The first proposal for power development at Orakei Korako was made in 1904, but it was not until 1955 that the scheme was finally approved. By May 1960 an earth-filled dam, rising 49 metres above the original river level, was placed and consolidated. The filling of Lake Ohakuri began on 19 January 1961 and was completed in 14 days. Two of the world's largest geysers were drowned by the lake: Minginui Geyser, which was once observed erupting up to 90 metres high (equal to the world's tallest currently