the site of an old Italian tunneling construction camp. Started by mountaineer Graeme Dingle in the 1970s, this centre offers valuable outdoor training experience and skills to secondary school groups and others. Train and engineering enthusiasts will enjoy the Raurimu Spiral. The main trunk rail line spirals upwards 132m via a tunnel and 180-degree hairpin bends so the passengers near the head of the train can see the rear carriages heading in the opposite direction. At the time of construction it was considered a masterpiece of engineering. This was the last stage to be built in the main trunk railway line completed in 1900. Cold Kiwi Motorcycle Rally The Cold Kiwi Motorcycle Rally, advertised as NZ's longest running motorcycle rally, has been held on the Plateau since 1972. The event is run by The Ruapehu Motorcycle Club in early September each year. Bikers sleep in their own tents despite the average temperature being −8 °C at night, but the club provides hot food and drinks, a bonfire, as well as competitions, souvenirs, live bands and toilet facilities. Tongariro Alpine Crossing The one-day Tongariro Alpine Crossing from the Mangatepopo Valley across Mt Ngauruhoe and Mt Tongariro is named one of the greatest one-day walks in the world by the Department of Conservation. The 19.2 km track is well marked in summer and popular but trampers should be quite fit and well equipped as the route is exposed, especially during the winter months (April to September) when the route poles are sometimes hidden by snow or blown away. There are two well equipped huts near the ends of route. Detailed guidance is available from the Mt Ruapehu Department of Conservation Visitors Centre. References Geology - South Auckland Land District, from An Encyclopaedia of New Zealand, edited by A. H. McLintock, originally published in 1966. Te Ara: The Encyclopedia of New Zealand, updated 26 September 2006. Accessed 2007-07-06. Landscape - North Island, from An Encyclopaedia of New Zealand, edited by A. H. McLintock, originally published in 1966. Te Ara: The Encyclopedia of New Zealand, updated 26 September 2006. Accessed 2007-07-06. Chapters 1-3, The Volcanic Plateau, District Report 07, Rangahaua Whanui, Waitangi Tribunal. Accessed 2007-07-06. Ignimbrite cliffs, from Eileen McSaveney and Simon Nathan. 'Geology – overview', Te Ara: The Encyclopedia of New Zealand, updated 13 April 2007. Accessed 2007-07-06. Tony Nightingale. 'Government and agriculture - State-funded research', Te Ara: The Encyclopedia of New Zealand,