See one of Hawaii's most scenic waterfalls via an easy 1-mile paved loop through a rainforest, past bamboo and ginger, and down to an observation point. You'll have a perfect view of 442-foot Akaka and nearby Kahuna Falls, which is a mere 100-footer. Keep your eyes peeled for rainbows. The noise you hear is the sound of coqui frogs, an alien frog from Puerto Rico that has become a pest on the Big Island.