Pearl Harbor was an extensive, shallow embayment called Wai Momi (water of pearl) in the region of Pu'uloa (long hill) by the Hawaiians. The first people to arrive on the island of O'ahu, around 100-300 BCE, would have seen verdant lands around the bay watered by streams running down from the Ko'olau Mountains, bordered by the arid 'Ewa Plain with its abundance of flightless land birds.