The forthcoming Fifth Generation (5G) era raises the expectation for ubiquitous wireless connectivity to enhance human experiences in information and knowledge sharing as well as in entertainment and social interactions. The promising Visible Light Communications (VLC) lies in the intersection field of optical and wireless communications, where substantial amount of new knowledge has been generated by multi-faceted investigations ranging from the understanding of optical communications and signal processing techniques to the development of disruptive networking solutions and to the exploitation of joint localisation and communications. Building on these new understandings and exciting developments, this paper provides an overview on the three inter-linked research strands of VLC, namely localisation, communications and networking. Advanced recent research activities are comprehensively reviewed and intriguing future research directions are actively discussed, along with the identifications of a range of challenges, both for enhancing the established applications and for stimulating the emerging applications.