The hikes at Haleakala are focussed on the levels of Haleakala mountain. The Summit District offers exploration of the sun-drenched"crater", which is actually a valley. The Kipahulu Area is rain-drenched, subtropical, lush and has many waterfalls. The 8.4 mile Kuapo Gap Trail descends from crater to the coast. The views along the way are stunning, and is a a good way to get a good cross-section of the ecological zones on the mountain. Hosmer Grove Trail is a fascinating interpretative walk that takes you through one of the park's "biological battlegrounds," beginning in an alien forest and ending in native Hawaiian shrubland.