 The border between Papua New Guinea and the Solomon Islands runs between these neighboring atolls, which form a small geographic group together with the wholly submerged Roncador Reef at the southern end.In Polynesian history, the main cultural and commercial exchanges took place with the inhabitants of neighboring Ontong Java Atoll, with whom Nukumanu people share many cultural affinities.Towards the end of the 19th century Nukumanu became part of the German colonial empire.