Fresh Water at the Bottom of the Sea Cliff

The last stretch of the staircase is different. The rock stops being dry. It goes darker and cooler under her feet, and there is a smell of wet stone, and the light coming up off the water throws moving lines across the ceiling of a low cave at the bottom.

And there, at the level of the sea, with salt water a few steps away, fresh water is coming out of the rock. Polly puts her beak to it. It is cold and it is sweet and it is entirely wrong, and it is the reason for everything above her.

It works like this. The land on top of the cliff is limestone, and rain does not run off limestone the way it runs off other rock. It sinks. It finds cracks and widens them and travels down through the inside of the stone, and because fresh water is lighter than sea water it can come all the way to the bottom of the cliff and arrive still fresh, right at the water line, before the sea gets a chance to mix with it.

So now the staircase makes sense. Not soldiers, and not one night. Monks, most likely, cutting patiently downward over years toward a spring they knew was there, because a town on top of a cliff can have walls and towers and a view over the whole strait and still lose everything for the want of a drink of water.