A cave system is a network of interconnected underground spaces formed by natural processes, primarily through the erosion of rock by water. These systems can vary in size and complexity, ranging from small caves to extensive networks that stretch for miles. They often contain unique geological features such as stalactites and stalagmites, which are formed by mineral deposits over time. Cave systems can be found in various environments around the world, including limestone regions, volcanic areas, and even ice caves. They provide habitats for diverse species, including bats and various insects, and are important for studying geology and ecology. Notable examples of cave systems include the Mammoth Cave in the United States and the Waitomo Caves in New Zealand.