Light confers spatial and temporal information to animal behavior. Neural pathways processing visual inputs partially overlap with those processing photic circadian information in vertebrates and arthropods. The simplicity of the Drosophila larval visual system makes it a unique model to address basic questions on how light information is processed and shared between rapid and circadian behaviors. The larval eye is composed of 12 sensory neurons that transmit information to a small number of target neurons including lateral neurons of the clock circuit and three glutaminergic optic lobe pioneer neurons (OLPs). Powerful genetic tools make Drosophila larvae an outstanding model that further allows us to explore the connectivity and how light-dependent navigation is driven. We have identified neural elements of the circuit and dissected their connectivity. Implementing high-resolution video tracking analysis allows us to assess the function of neurons for distinct aspects of navigational decision making. Integration of anatomical, functional and connectomics allows us to move forward to build a functional map of a simple visual circuit.