We are 15 metres underground in a silent, echoing cave.  Only the solemn plop of icy, freshwater can be heard, woven between our awed whispers.  I take two big breaths, the chill of the encompassing sapphire water temporarily forgotten.  Two metres down, with lungs bursting only moments after a big breath, I turn underwater to head through to the next cave.  My thrashing arms and legs fight for propulsion and I feel stuck in a current that does not exist!  Suddenly I see the torchlight from our guide in the next submerged cave and head to the surface, seeking much-needed oxygen.  I am that close to being able to breathe again, I think I can just make it, when a firm hand reaches down and pushes my head back under.  I am coming up too early, my soft head-on course for sharp, jagged rock.  Fighting to withhold my panic I swim further along and the hand releases me, I break back into my world with the sweet smell of air.  In reality, I have been underwater a few seconds and swam a few metres.  “That was pretty easy” I grin.