Political map of Australia, New Zealand & the Southwest Pacific 31 December 1936 (Exploration of the New Guinea Highlands): Prior to 1930, the mountainous interior of New Guinea (New Guinea highlands) was largely unexplored and thought to be mostly uninhabited. Then in the early 1930s Australian and Dutch patrols finally began penetrating the highlands with the aid of aircraft. To their surprise they discovered numerous populous villages and a rich variety of cultures - over a million people previously unknown to the outside world.