By 1790 Kamehameha the Great had conquered Maui, Lanaʻi and Molokaʻi. But power over his home island of Hawaiʻi was a challenge. When told by a prophet that he'd rule all of the Hawaiian Islands if he built a heiau dedicated to his war god Kukaʻilimoku atop Puʻukohola (Whale Hill) in Kawaihae, Kamehameha built this massive structure.
He and his men formed a human chain 20 miles long, transporting rocks hand to hand from Pololu Valley in North Kohala. After finishing the heiau by summer 1791, Kamehameha held a dedication ceremony and invited his cousin and rival Keoua, chief of Kaʻu. When Keoua came ashore, he was killed and taken to the luakini heiau (temple of human sacrifice) as the first offering to the gods. With Keoua's death, Kamehameha took sole control of the Big Island and by 1810 ruled the Hawaiian Islands.
Back then Puʻukohola Heiau was adorned with wooden kiʻi (statues) and thatched structures, including an oracle tower, an altar, a drum house and shelter for the high priest. After Kamehameha's death in 1819, his powerful widow Kaʻahumanu and son Liholiho, who abolished the kapu (taboo) system, destroyed the deity images and the heiau was abandoned.
Today, only the basic rock foundation remains, but it's still a massive 224ft by 100ft, with 16ft- to 20ft-walls. To get here, turn makai off the Akoni Pule Hwy halfway between mile markers 2 and 3.
