In 1972 an image became an icon: 'Blue Marble', a photograph of the Earth as seen from outer space. The picture features prominently the globe's water-covered surface. The ocean connects nature and culture in the modern world. Within the time-span of 100 years, the sea changed its cultural meaning, from a dangerous place to an endangered environment. This volume traces diverse processes of oceanic transformation in the Anthropocene: it follows scientists, seafarers, diplomats and filmmakers from ship-decks to the arenas of political decision making on land. The essays lead from underwater dumping grounds to islands in the south pacific. Tiny organisms like plankton and charismatic megafauna like whales accompanied the human voyages. The presence of the animals challenges common notions of human culture. The global age has to take non-human agents into account to fully understand the cultural history of the seas.