Oceans have held varying places in the imagination of societies, always linked to particular cultures and shifting in line with predominant world views and developing socio-economic and technological capacities. This chapter presents three Western ways of looking at the ocean. Each emerged at a particular period, but all continue to shape today’s conceptions of the ocean. There are many other ways of conceptualising the ocean, and different concepts exist concurrently, resulting in a multiplicity of perspectives that are changing over time. Although some scholars are debating whether it is possible to know the ocean at all, the selected concepts—incomplete though they may be—also point to contradictory perceptions of the ocean that may have a bearing on how we do maritime spatial planning.