From above, the shape of the island vaguely resembles a fork, with its two nearly symmetrical bays opening to the north side of the island: Cook’s (or Paopao) Bay and Oponohu Bay. The island was formed as a volcano 1.5 to 2.5 million years ago, the result of a geologic hotspot in the mantle under the oceanic plate that formed the whole of the Society Archipelago. It is theorized that the current bays were formerly river basins that filled during the Holocene searise.