Smell 'sensations' are among the most mysterious of conscious experiences, and have been cited in defense of the thesis that the character of perceptual experience is independent of the physical events that seem to give rise to it. Here we review the scientific literature on olfaction, and we argue that olfaction has a distinctive profile in relation to the other modalities, on four counts: in the physical nature of the stimulus, in the sensorimotor interactions that characterize its use, in the (...) structure of its intramodal distinctions and in the functional role that it plays in people's behaviour. We present two thought experiments in which we detail what would be involved in transforming sounds into smells, and also smells into colours. Through these thought-experiments, we argue that the experiential character of smell derives precisely from the structural features of olfaction, and that an embodied account of olfactory phenomenology is called for. (shrink)