Beginning in 1903 with the creation of Wind Cave National Park, ten National Park Service units have been created because of the caves they contained. Since the establishment of the National Park Service in 1916, over 5,360 caves are known to exist within at least 99 park units. These caves are found in different types of rocks and were formed by several different mechanisms. The most prolific landscapes that have formed caves are those in soluble rocks such as limestone. Known as karst landscapes, at least 114 park units contain some amount of karst. In the early days, cave parks were developed for their commercial and recreational values. Little was known of the processes that created caves or the many resources that encompassed these entire landscapes. With the help of cave and karst enthusiasts and researchers, and the advent of cave and karst resource managers, the National Park Service has made great strides in understanding these resources. This has led to increased educational opportunities and better management decisions that will enhance long-term preservation of these resources.