Mammoth, << MAM uhth, >> Cave National Park surrounds Mammoth Cave, part of the world’s longest known cave system. The park lies in central Kentucky. The Green and Nolin rivers flow through it. Mammoth Cave National Park was established in 1941. For area, see National Park System (table: National parks).
Mammoth Cave is often called one of the wonders of the Western Hemisphere. The cave is in a ridge that consists mainly of limestone. Through millions of years, mildly acidic water trickled through cracks in the limestone and wore it away, forming the cave. Visitors can take guided tours through various parts of the cave. The lowest level lies 360 feet (110 meters) below the surface. Many rocks in the cave have interesting colors and shapes. These rocks resemble flowers, trees, and waterfalls.
The cave contains several lakes, rivers, and waterfalls. The largest river, Echo River, varies in width from 20 to 60 feet (6 to 18 meters) and in depth from 5 to 25 feet (1.5 to 8 meters). Strange eyeless fish live in Echo River (see Cavefish). These colorless creatures are about 3 inches (8 centimeters) long. Other blind creatures living in Mammoth Cave include beetles and crayfish. Several species of bats live in parts of the cave.
Historians believe that the first white people to see Mammoth Cave were local settlers who came to the area during the late 1700’s. A deed filed in 1798 describes a large cave that probably was Mammoth Cave. But moccasins, simple tools, torches, and the remains of mummies found in the cave indicate that it was known to prehistoric Native Americans. Saltpeter, used to make gunpowder, was mined in the cave during the War of 1812. Mammoth Cave contained the only large supply of saltpeter that was known in the United States at that time. After the war ended, miners stopped working in the cave. It became a public showplace in 1816.
Another famous cave, Floyd Collins Crystal Cave, lies within the national park. Collins, a cave explorer, discovered Crystal Cave in 1917. Crystal Cave forms part of the Flint Ridge cave system, one of three cave systems in the park. The other two are the Joppa Ridge and the Mammoth Cave systems. In 1972, explorers discovered a connection between Mammoth Cave and the Flint Ridge cave system. The combined Mammoth-Flint Ridge cave system is the longest known cave system in the world. It has more than 300 miles (480 kilometers) of explored passages.
