Viewpoints of geologic and scenic interest along Wailuku River. Boiling Pots is a succession of big pools connected by underground flow or cascades and whose waters roll and bubble as if boiling. The exposed hexagonal columns that line the pools were formed by the slow cooling of basalt lava. The 80-foot Rainbow Falls is renowned for the rainbow formed from its mist many mornings. Legends say that the cave beneath the waterfall was the home of Hina, mother of the demigod Maui.