I drove to the top of Haleakalā. It is 10,023 feet high. The Hawaiian Islands are the tops of volcanoes that grew from the ocean floor. Haleakalā is located on Maui, one of the biggest volcanoes in the world. The “crater” was actually formed by erosion. Most of the volcanoes on the Hawaiian Islands are shield volcanoes, unlike Japan and South America, which are composite.