© Slovenská pošta, a.s., 2006 Slovakia, despite its relatively small area, is characterised by a very diverse and complicated geological structure. Endogenous and exogenous processes continually repeating and alternating with each other have determined - during their intricate evolution - the variability of the rock. The important part of the endogenous processes is volcanic activity, the result of which is the birth of volcanoes that have produced a wide spectrum of volcanic rocks. Under the influence of changes of climatic factors (temperature, wind, precipitation), the exogenous processes cause the weathering of rock surface layers, and transport the products of such erosion...