Read more: Everything You Need To Know Before Taking A Solo Backpacking Trip Once you've determined that a cave is safe for shelter, it's time to make it work for you in your survival situation.

and salt yoga to re-create the experience in these caves. One is now open at Saks Fifth Avenue. But nothing beats the magic of the mines. People swear the air inside salt mines holds curative ...

But extracting the coveted salt means descending into dark caves, then blasting and carrying heavy rock. Faizan Panjwani: The problem is the massive size of the blocks that come from the mine.

Israeli researchers say they have discovered the world's longest salt cave. The 10km (6.2 miles) of passages and chambers inside Malham Cave, overlooking the Dead Sea, were mapped out over two years.