Sources of heat should be taken into consideration when speaking about the hot springs. It's a common knowledge that hot springs are referred to as natural discharges of water from the ground which have an elevated temperature. Most hot springs are known to result from the groundwater emergence that has passed near recently formed igneous and hot rocks. Among the countries which are pretty popular for their hot springs are USA, Iceland, New Zealand (North Island in particular). It's worthy admitting that there has been a great interest in utilizing the energy contained in almost all hot springs. As a matter of fact, one of the most common sources of heat is geothermal energy which is already being utilized in Iceland, Italy and USA (California). So, the water issuing from hot springs is usually heated by the geothermal heat from the Earth's interior. Generally speaking, the temperature of the rocks inside the Earth is increased with depth. It is called geothermal gradient. When the water percolates deeply into the crust it is heated because it comes in close contact with hot rocks. As a matter of fact, the water from hot springs is heated in the described manner (particularly in non-volcanic areas). Speaking about the hot springs located in volcanic areas it's necessary to pay attention to the fact that water is heated there due to the contact with molten rock (magma). It can be seen at the hot springs located in Yellowstone National Park of the USA. Be aware that in such areas hot spring are often of or near the boiling point and some people may become seriously burned by accidentally entering such areas - real sources of heat. Sometimes water can even boil or become superheated. If so, it is likely to build steam pressure and erupt in a jet above the Earth's surface which is scientifically called "geyser". In most cases water just reached the ground in a form of steam; it is called fumarole. In some areas the water is mixed with clay and mud - then such spring is referred to as a mud pot. Some warm springs are sometimes caused by cold and hot springs mixing but appearing outside the geothermal areas (for example, in Georgia). In recent years hot spring systems have become an outstanding source of alternative energy of great importance. Geothermal energy is known to come from the heat in the crust of the Earth. As it has already been mentioned this energy heats the rocks in places where magma or molten rock is very close to the Earth's surface. These rocks heat the water underground and therefore - produce steam or hot water. This brings the necessary geothermal energy to the surface. In some cases ground water naturally rises to the surface and form hot springs and geysers. In other places people tend to use steams and hot water by special sinking pipes into the ground and directing the water to particular places where it is mostly needed and can do useful work. Thus, it's very important to have enough information about hot springs and sources of heat and use this data taking into account all the benefits of hot springs.