The Amazing Human Microcosm The microscopic world is all around us and within us. Billions of bacteria, viruses, fungi, are on every surface we touch, the food we eat, the air we breathe. They are on our skin, in our mouths, nose and eyes, and live comfortably throughout our bodies, their homes. They live inside our cells and even incorporate their DNA into ours. In fact we are more bacteria than human! Ninety per cent of the cells in your body belong to bacteria, not you.