The Pīpīwai Trail is the best hike on Maui, starting from the Kīpahulu Visitor Center in the coastal section of Haleakalā National Park and climbing 4 kilometres (one way) to Waimoku Falls, a 122-metre cascade plunging off a basalt cliff into the forest below.
The first stretch crosses the Oheo stream above the famous pools and passes through open coastal scrub and forest. The middle section enters a dark, cathedral-like bamboo grove that goes on for the better part of a kilometre — one of the most atmospheric walks in Hawaii. The trail ends at the base of Waimoku Falls, which drops in a single unbroken curtain. Take water, wear shoes that can get wet, and allow at least three hours return.
Note that Kīpahulu is only reachable by the Road to Hāna, not from the Haleakalā Summit district. The two sections of the national park are separate. Entry requires the national park fee; reserve a timed entry if driving from Hāna.