Water from the falls, situated on the eastern coast of Amami-Oshima island here, tumbles 181 meters down a mountain cliff into the Pacific, the city government said Sept. 10 when it posted an image of the yet-to-be-named cascade on the city's website. Fishermen and amateur water sports enthusiasts knew about the existence of the waterfall, but only from the parts visible from the sea. They had no idea of its full grandeur. Futoshi Hamada, a 68-year-old photographer who lives in the city of Amami, operated a drone on several occasions from May last year to capture full footage of the falls. He turned over the material to the city government, which then used satellite survey methods this past August to calculate the drop height, officials said. Amami-Oshima was inscribed in the list of UNESCO World Natural Heritage sites this past summer. "There are still unknown territories on this island," Hamada said. A roughly 100-meter section can be viewed from the sea, but the coast near the waterfall is a rocky tract with rough waves and not easily accessible, he added.