With approximately 7,500 recorded caves in the state, Missouri has become known as the Cave State. Many areas of the state are underlain by soluble carbonate bedrock, such as limestone or dolomite, that can be easily dissolved by water. Slightly acidic rainwater filters into the ground and enters cracks and joints found in the bedrock; slowly dissolving it away. In time, the groundwater enlarges these passages to form caves. The water moving through caves can deposit minerals from the dissolved rock creating speleothems, or cave formations. Caves are identified as either commercial or wild. A commercial cave, or show cave, is one that is accessible to the public for guided visits. Wild caves are in their natural state and have not been altered. The artists of Anderson Design Group rendered this classic poster design in the spirit of a vintage travel poster. This original illustration is available as a poster, print, notecard, postcard, canvas, or metal sign.