The Top 5 Longest Caves on Earth

	Cave	Location	Known Length (km)	Known Length (mi)
1	Mammoth Cave System	Kentucky, USA	590,629 km	367.000 mi
2	Optimisticeskaja	Ukrainskaja, Ukraine	214,000 km	132.973 mi
3	Jewel Cave	South Dakota, USA	207,718 km	129,069 mi
4	Hoelloch Cave System	Schwyz, Switzerland	191,909 km	119.247 mi
5	Wind Cave	South Dakota, USA	186,780 km	116.060 mi