Waterfall at Shiratani Unsuikyo Ravine is a lush nature park containing many of Yakushima island's ancient cedars. The park offers a network of hiking trails that run along the ravine varying in length from one to five hours long, though many prefer to choose their own routes among the paths. The trails vary in difficulty from basic footpaths to developed paved paths using stone and wood. One of the main attractions of Shiratani Unsuikyo is a part of the forest that served as the inspiration for the Studio Ghibli animated film Princess Mononoke. Oga Kazuo, the lead artist for the film, spent lots of time here working on sketches for the movie's forests. Besides the ancient cedar trees, some of them thousands of years old, the continually wet microclimate protects the cedars by enabling them to produce more than usual resin, It also is an ideal climate for moss, which grows everywhere here.