Rotorua is known as the thermal wonderland of New Zealand. Its hot springs and geysers have attracted tourists for over a hundred years. Rotorua sits on the shores of Lake Rotorua. Rotorua is built over a geothermal hot spot. There are numerous natural vents, hot pools and other geothermal features in and around the city. Many of these are in parks and reserves. Geologically, Rotorua is in the middle of the Taupo Volcanic Zone, which is named after Lake Taupo, the largest volcano in the area. There are four major volcanic calderas, which now contain lakes, and several more recognisable volcanoes in the surrounding area. It is this geologically active zone that produces the heat that is needed to drive all the geothermal activity. http://wikitravel.org/en/Rotorua