تعريف jewel cave national monument في الإنجليزية الإنجليزية القاموس.
National monument, southwestern South Dakota, U.S. Established in 1908, it occupies an area of 2 sq mi (5 sq km). It is noted for its limestone caverns, a series of chambers joined by narrow passages. The known length of the caverns is 77 mi (124 km)