...In my local swimming pool.
Rah #1: Did you know that a cubic litre of water weighs one tonne?
Rah #2: Really? 'Cos it doesn't feel that heavy when you're under the surface.
There's so much wrong here I don't know where to start. It would be nice to believe these two weren't our students, but I suspect this is a vain hope.
On the other hand, I swam my first mile today. I realise it could be considered slightly pathetic that it has taken me 28 years to have gotten round to it, but when my father was my age he couldn't swim at all, so I guess we're making progress as a bloodline.