A moment of perfect calm: on the beach late on a summer evening, the sun gone down but a gentle glow still in the sky. The sea is moving slowly, steadily, with great power, almost silver and black in the fading light. The sound of the waters breaking mingles with the haunting Celtic music from my headphones, and time goes away for a second, an eternity.
Another: sitting on the grass in the sunshine, feeling the warmth pour into me, watching a ladybird patiently climb a blade of grass with no hurry or worry or fuss. In her smallness, she is perfect and beautiful.
Another: the Egyptian room of the museum. It should seem a morbid place, filled with the bodies and possessions of the dead, but it is curiously peaceful. There is a stillness there, in the middle of the busy city.
There are others, but if there were not these would suffice: they are the places I go to in my mind when I need to feel some calmness, a little tranquillity.