Seven Islands is a Core Prime map that is mostly comprised of a large aqueous body, with the eponymous seven islands scattered around it in a rough heptagonal formation. As with all Core Prime maps, building a Metal Extractor or Moho Mine anywhere on the islands will generate the maximum amount of metal, rendering it unnecessary to build Metal Makers and Moho Metal Makers; despite Seven Islands being a map that was available prior to The Core Contingency, Underwater Metal Extractors will also generate the maximum amount of metal, the only other pre-Core Contingency map with this feature being Over Crude Water (a Core Prime map with water). At a size of 40 x 40, Seven Islands is the largest Cavedog map in Total Annihilation.