If you're looking for adventure then look no further than Aogashima Island. Situated in the Philippine Sea over 350km south of Tokyo, the only way to get there is by helicopter or by boat. The island, which covers an area of less than 9km2 and houses fewer than 200 inhabitants, is most well known for its unique geological formation. Not only does Aogashima have a volcanic crater at its centre - the crater is actually situated in the middle of a second, larger volcanic crater! The result is both beautiful and awe-inspiring,  and whoever braves the long journey to Aogashima Island will be rewarded with a truly memorable experience.