Missouri is often called the “cave state” as we have a large region of karst topography, which includes extensive deposits of limestone and dolomite that have been broken down by flowing water over time to form caves, sinkholes, springs and natural bridge features. Missouri has over 7000 caves, most of which are found in the karst region. The main type of caves found in Missouri are solutional caves. These happen to be the most common type around the world, so that is what we will focus on for this lesson. Solutional caves form when acidic groundwater seeps through porous rock like limestone and wears away the rock over time. The caves that form can grow to be massive, and they can support interesting creatures with unique adaptations for living in darkness. They also have different zones and unique features that form over thousands of years.