Kircher's geological world map. Map of the world showing geological features, from the work Mundus Subterraneus (Dutch 1668 edition) by the German Jesuit scholar Athanasius Kircher (circa 1601-1680). The map is labelled in Latin, with a title and key across top. Volcanoes and oceanic vents are marked, illustrating Kircher's theory that underground water, heated by the Earth's internal fires, caused the tides and the eruption of volcanoes. The geography of the map shows the areas reached by European explorers, with Australia (lower right) and New Guinea (far left) yet to be fully mapped.