Each year millions of animals undertake remarkable migratory journeys, across oceans and through hemispheres, guided by the Earth’s magnetic field. The cellular and molecular basis of this enigmatic sense, known as magnetoreception, remains an unsolved scientific mystery. One hypothesis that attempts to explain the basis of this sensory faculty is known as the magnetite theory of magnetoreception. It argues that magnetic information is transduced into a neuronal impulse by employing the iron oxide magnetite (Fe3O4). Current evidence indicates that pigeons employ a magnetoreceptor that is associated with the ophthalmic branch of the trigeminal nerve and the vestibular system, but the sensory cells remain undiscovered. The goal of this ambitious proposal is to discover the cells and molecules that mediate magnetoreception. This overall objective can be divided into three specific aims: (1) the identification of putative magnetoreceptive cells (PMCs); (2) the cellular characterisation of PMCs; and (3) the discovery and functional ablation of molecules specific to PMCs. In tackling these three aims this proposal adopts a reductionist mindset, employing and developing the latest imaging, subcellular, and molecular technologies.