When you swim, you feel your body for what it mostly is — water — and it begins to move with the water around it… The swimmer experiences the terror and the bliss of being born. So swimming is a rite of passage, a crossing of boundaries: the line of the shore, the bank of the river, the edge of the pool, the surface itself. When you enter the water, something like metamorphosis happens. Leaving behind the land, you go through the looking-glass surface and enter a new world, in which survival, not ambition or desire, is the dominant aim… You are in nature, part and parcel of it, in a far more complete and intense way than on dry land, and your sense of the present is overwhelming. Roger Deakin, ‘Waterlog: A Swimmer’s Journey Through Britain’