Cwm Idwal. The mountains rise around a lake, creating a craggy bowl blasted with shadows and light. The water on the lake ripples like shards of mirrored glass. Everywhere there are signs of collapse: boulders torn down the mountain side, cascades of tiny shards of rock and slate. We clamber up the hillside, mounting great boulders, moving with all of our bodies, hands grasping moss and grass, crushed bilberry like blood in the palm. Mist in the heights gathers like a menace but the shadows are pleasingly cool, out in the light the heat burns the salt on the back of my neck and the air is too unforgiving. We cross waterfalls, sit restful on rocks overhanging the water. There is silence here, and the sound of our breathing loud in our ears. My heart beats, and I feel it.