The main feature of this part of the park is Haleakalā Crater which, despite its name, is geologically an erosional valley. It is across, wide, and deep. The interior of the crater is dotted by numerous volcanic features, including large cinder cones. Two main trails lead into the crater from the summit area: the Halemau'u and Sliding Sands trails. Hikers in the crater can stay in one of three cabins.