80 cave explorers from nine countries have mapped Israel’s Malcham cave near the Dead Sea and declared it to be the longest salt cave in the world.  At 10km it dwarfs Iran’s 6.5km 3N cave – the previous longest. Malcham is in Mount Sdom – where, in the Bible, Lot’s wife was turned into a pillar of salt.

https://www.timesofisrael.com/a-hollow-victory-israel-claims-title-of-worlds-largest-salt-cave-from-iran/

http://www.israelnationalnews.com/News/News.aspx/261038