A major island group in the south-central Pacific Ocean about 1,600 miles (2,600 km) northeast of New Zealand. American Samoa, a dependency of the United States, consists of the six islands. Western Samoa, an independent nation, consists of the nine islands. The islands were settled by Lapita colonists in the late 2nd millennium BC. There is a pottery sequence through the 1st millennium BC, after which pottery manufacture ceases. On the evidence of adze typology, Samoa may have been the source of the first settlers to penetrate eastern Polynesia, perhaps to the Marquesas, in the early 1st millennium AD. The last 1500 years of Samoan prehistory are associated with above-ground monuments, including earthwork forts, earth or stone houses, god-house platforms, and agricultural terraces.