Over the last years, international sea-freight container transportation has grown dramatically and container terminals play nowadays a key-role in the global shipping network. The increased competitiveness among terminals requires more and more efficiency in container operations, in order to minimize ships turnaround time. In this work, we focus on the optimization of yard operations, which are critical for the terminal efficiency, because of their impact on all the other operations (most operations originate or end in the yard). Firstly, we give an overview of problems which arise in the management of a container yard (e.g.stacking policies for import and export containers, re-marshalling strategies, yard crane deployment and scheduling) and we briefly describe models and methods presented in the literature. Then, starting from a collaboration with some of the busiest ports in Europe, we describe more in depth a new yard-related problem, which represents -in our opinion- the current new challenge: the management of transshipment operations. In particular, we present a model for their optimization. Finally, we suggest further steps and possible research directions.