Devil's Icebox (cave)
Devil's Icebox is a cave located in Rock Bridge Memorial State Park in Columbia, Missouri. It is said to be one of the longest caves in the state of Missouri and is one of the caves with the highest number of species in the state. It is currently closed to protect the endangered Indiana bat, and is the only known natural home of the species Kenkia glandulosa or pink planarian. Name 

The cave was probably given the name Devil's Icebox by people living in area during the early 1800s. The word icebox in the name probably came from the very cold air that leaks from the cave all year. In 1926, the name of the cave was printed in an article about the earliest exploration of the cave in 1924. History 

The stream that flows through Devil's Icebox Cave was a source of power for settlers in the 19th century. The earliest exploration of the cave took place in 1924. A man named Ben M Yates claimed he was the first one to explore that cave, he along with his sons went into the cave with a john-long boat and other items. They were said to have explored the cave for 24 hours and traveled 5 miles. Access to the cave was restricted in 2006. Then in 2010, tours to the general public stopped to protect the bats from white-nose syndrome. Despite this, the disease affected the caves in Rock Bridge during 2013. Characteristics

Temperature 
The cave is said to be as cold as 56 degrees all year round. It is also said to have a temperature of 13 degrees. Species 
According to the U.S. Government Printing Office, Devil's Icebox has the second highest number of species out of the over 6000 caves in Missouri. In 2007, 80 species have been identified in the cave. It is the only place where the species Macrocotyla glandulosa has been found; the rarity of this species was once used as an argument to prevent the construction of a shopping mall in the area. The cave is also home to species of salamanders, frogs, troglobites, millipede, spiders, and springtail. There are even endangered bat species like Myotis sodalis, Myotis septentrionalis, and Myotis grisescens in the cave. Length 
It is said to be the seventh or sixth longest cave in Missouri, with it spanning 7 miles. In the year 1986 its length was measured to be over 30 thousand in feet, 5.76 miles, and 9.27 kilometers. Geology 

The cave is a double sink hole. It was formed in Burlington Limestone which had formed 300 million years ago. The cave is an example of karst topography. According to J Harlen Bretz, Devil's Icebox is a phreatic cave system. In January 1994, a stream in the cave was oversaturated with calcite and dolomite. In 2017 stalagmites in the cave were studied. All the water flowing in the cave is from the surface. References 

Caves of Missouri
State parks of Missouri
Sinkholes of the United States
Geography of Columbia, Missouri
Landforms of Boone County, Missouri
Limestone caves