http://cavingnews.com/20150113-south-dakotas-jewel-cave-nearing-175-miles-long
Posted by Dean
Amazing:
Jewel Cave is currently the third longest known cave in the world behind Kentucky’s 400 mile (643.7 kilometer) long Mammoth Cave System and Sistema Sac Actun in Mexico’s Yucatán Peninsula, at 206.9 miles (332.9 kilometers). image2048×1325 347 KB
Jewel Cave is currently the third longest known cave in the world behind Kentucky’s 400 mile (643.7 kilometer) long Mammoth Cave System and Sistema Sac Actun in Mexico’s Yucatán Peninsula, at 206.9 miles (332.9 kilometers).
