The Koana Islands lie south of the equator, between Madagascar, Indonesia and Australia. The archipelago includes 32 islands, with a total of 93 million residents. The reason you've not heard of it before is that it does not really exist. The nation was invented by an Australian train driver called Ian Silva, and the incredible maps he has produced of the islands are well worth investigating.
You can read an article about Silva's work, including links to more images, by clicking on the map below.