Ikeshima is an old coal mining island in Nagasaki Prefecture, just like the more famous Gunkanjima. Unlike Gunkanjima, Ikeshima isn't completely abandoned. There is still about 150, mostly very old people living on the island. Back in it's prime there was around 8000 people living on this island. There's still a functioning school built for a 1000 kids that now only has 2 students.
While Gunkanjima has become super famous and is completely flooded with tourists now, Ikeshima remains almost completely obscure. Which makes it a super cool place to explore. Its so quiet and peaceful and the small amount of residents gardening in between all the massive abandoned buildings almost seem like ghosts.