This is the famous ancient battlefield. Iao Valley State Park climbs Iao Needle to watch the fourth largest mountain springs on Maoyi Island. The forest here is dense and lush, and it is regarded as a place blessed by the local people. There is a 686-meter rock spike (Iao Needle) standing between the mountains, like a green spire towering into the clouds, is one of the famous landmarks of Maoyi Island. In 1790, it was used as a watchtower for the Maui Army. Later, King Kamehameha led the army to the island and defeated the Maui Army led by King Kahekili in the fierce battle. It unified the islands and changed the history of Hawaii.