Piʻilanihale Heiau

Towering above Kahanu Garden, a branch of the National Tropical Botanical Garden, is what is believed to be not only the largest heiau (ancient temple) in Hawaii, but also the largest in all of Polynesia. Piʻilanihale (House of Piʻilani) Heiau on Maui, a basalt mound 341 feet high and 415 feet wide, is believed to date back to around AD 1200, also making it one of the oldest structures on the islands.

Little is known about the history and exact usage of the site. However, the heiau was likely built in several stages, one of which was likely constructed by King Piʻilani, who unified Maui in the 16th century. In total, it likely took over 128,000 man-days to complete the temple, with some stones coming from as far as seven miles away at Hana Bay! Due to its architectural importance and notability, Piʻilanihale Heiau was designated a National Historic Landmark in 1964.

In addition to the heiau, the rest of Kahanu Garden is also worth visiting for its collection of native and "canoe" (introduced by Polynesians) plants. In particular, it boasts the world's largest collection of breadfruit plants.