List of longest caves

Columns: System | Length | Location | Discovery | Associated parks , protected areas
Mammoth Cave | 667.8 km ( 415.0 mi ) | near Brownsville , Kentucky , United States | 1791 | Mammoth Cave National Park , also a World Heritage Site and International Biosphere Reserve | Sistema Sac Actun / Sistema Dos Ojos | 371.9 km ( 231.1 mi ) | near Tulum , Quintana Roo , Mexico | 1987 | none | Jewel Cave | 334.8 km ( 208.0 mi ) | near Custer , South Dakota , United States | 1900 | Jewel Cave National Monument | Sistema Ox Bel Ha | 271.0 km ( 168.4 mi ) | near Tulum , Quintana Roo , Mexico | 1996 | southern parts in Sian Ka'an Biosphere Reserve | Shuanghedong Cave Network | 257.4 km ( 159.9 mi ) | Guizhou , China | 1988 | Suiyang Shuanghedong National Geopark | Optymistychna Cave | 257.0 km ( 159.7 mi ) | near Korolivka , Ukraine | 1966 | Dnistrovskyy Canion | Wind Cave | 245.1 km ( 152.3 mi ) | near Hot Springs , South Dakota , United States | 1881 | Wind Cave National Park | Lechuguilla Cave | 241.4 km ( 150.0 mi ) | near Carlsbad , New Mexico , United States | 1900 | Carlsbad Caverns National Park | Clearwater Cave System | 227.0 km ( 141.1 mi ) | near Miri , Sarawak , Malaysia | 1978 | Gunung Mulu National Park , also a World Heritage Site | Fisher Ridge Cave System | 209.2 km ( 130.0 mi ) | near Brownsville , Kentucky , United States | 1981 | partly within Mammoth Cave National Park | Hölloch | 201.9 km ( 125.5 mi ) | Muotathal , Switzerland | 1875 | none

Example questions:
In what year was the longest cave in Eurasia discovered ? | When was the national park that includes the longest cave in the world created ? | What is the Engish name of the long cave located in Muotathal ? | The city that the long Lechuguilla Cave is located in is the seat of what county ?

Answers:
1966 | July 1 , 1941 | Hellhole | Eddy County