A biomimetic artificial eye. Gu et al.1 report an artificial visual system that mimics the human eye. A lens is fixed over an aperture in an ‘eyeball’, which consists of a metal shell at the front, an artificial retina at the back and an ionic liquid in the middle. The key advance is the hemispherical retina: a dense array of light-sensitive nanowires held in the pores of an aluminium oxide membrane. The nanowires mimic the photoreceptor cells in biological retinas. A polymeric socket holds the retina, ensuring electrical contact between the nanowires and liquid-metal wires at the back.