I’ao Valley, Maui
Iao Needle (Kūkaemoku), an East Maui landmark, is a vegetation-covered lava remnant rising 1,200 feet from the valley floor or 2,250 feet above sea level. The needle is a sharp ridge that gives the appearance of being a spire when viewed end-on.  The needle is an extension of and surrounded by the cliffs of the West Maui Mountains, an extinct volcano. There is a short trail (Iao Needle Lookout Trail and Ethnobotanical Loop) to a windy overlook.
‘Iao Valley is a popular tourist destination where people come to hike the grounds and gaze at the unusual phallic rock that rises from the stream. Just a short drive from Kahului and Wailuku in central Maui, the park features Kepaniwai Heritage Gardens, which honors the diverse cultures that have immigrated to Maui, and Hawaii Nature Center, an interactive educational center located just above the Heritage Gardens.
The Hawaiian god Kāne is considered to be the procreator and the provider of life. He is associated with wai (fresh water) as well as clouds, rain, streams, and springs. Kanaloa, the Hawaiian god of the underworld, is represented by the phallic stone of the Iao Needle. Kapawa, the king of Hawaiʻi prior to Pili, was buried here. Maui ruler Kakaʻe, in the late 15th century, designated Iao Valley as an aliʻi burial ground. The remains were buried in secret places.
Ancient Hawaiians named this valley ‘Iao (Supreme Light) in honor of the god ‘Io, and people came to the site to pay tribute to this important deity. The strange rock pillar that rises out of ‘Iao Stream, and is now called ‘Iao Needle, was once used as a natural altar.
Battle of Kepaniwai, Battle of the Dammed Waters
In his quest to conquer the islands, Kamehameha I set out to control the island of Maui in 1790. Maui’s King Kahekili II was on Oʻahu at the time. Kamehameha and 1,200 of his Hawai’i Island warriors landed in Kahului, Maui. He pursued Kahekili’s son Kalanikupule and other Maui chiefs deep into ʻĪao Valley.
The Maui warriors held off Kamehameha and his warriors for two days. On day 3 of the battle Kamehameha ordered for two western cannons, operated by two of his foreign advisors, John Young and Isaac Davis. Many of their warriors died in the bloody battle; their bodies lay in the stream blocking the flow of water. Kepaniwai, “the damming of the waters”.
None of Maui’s chiefs were killed, escaping through the mountains to the safety of Olowalu and Lahaina. After Kamehameha’s battle victory, Maui Chiefess Kalola accepted Kamehameha’s protection and offered her 11 year old granddaughter Keopuolani to him as a future wife.
Despite the defeat of his Maui forces, Kahekili refused to relinquish control of Maui; A year later he acquired cannons of his own and invaded the island of Hawaiʻi, but was unsuccessful. Kahekili died in 1793, Kamehameha returned to conquer & fully control Maui in 1794.