How are volcanoes born, in which way do they live, and why and when, eventually, do they become extinct? More specifically, why are there any polygenetic central volcanoes at all? Why is the volcanism not simply evenly distributed through the volcanic zone or field? There are certainly volcanic areas where the volcanism is more or less evenly distributed – such as at fast-spreading ridges. But for most other volcanic areas one or more locations within the area dominates the volcanism, resulting in the formation of a specific central volcano. The central volcano erupts much more frequently than its surroundings and, therefore, normally forms an edifice. The edifice is a structure with a certain mechanical strength, most of which derives from the internal structure of the volcano. Later in the evolution of the volcano, it may form a collapse caldera, as well as being subject to lateral collapses, all of which affect its shape. When, eventually, the supply of magma to the volcano is cut off, it becomes extinct, that is, dies.