Underground power cables and submarine power cables are crucial components supporting the energy transition. The importance and variety of interesting subjects related to (underground and submarine) power cables is often under-estimated. While many people initially think of cables to be simple components of minor importance, once one learns about power cables in electrical energy systems, it becomes clear how much there is to know about these components, how crucial they are in any energy system and the fact that they are one of the essential enablers of the energy transition. Think for instance about (underground or submarine) cable connections to windfarms, distribution cables connecting the renewable distributed energy sources and (often long submarine high voltage) interconnecting cables connecting two grids. Power cables are often a considerable part of the investment of such projects or any grid, while they also have a significant impact on the overall grid reliability. As the rate of power cables is extremely high in The Netherlands, much knowledge is available, but subjects will be treated from an international point of view. Several subjects will be discussed from an historical point of view and, of course, with an eye on the future taking especially the link to the energy transition into account.