Located in central Kyushu, halfway between Kumamoto and Beppu, is Aso-san, the worldâ€™s largest volcanic caldera. Up to 15 miles wide in spots, it was formed by a gigantic explosion about 100,000 years ago. Of the five volcanic cones contained within the caldera, one is still active, with the last eruption in 1990. There is a ropeway to the rim of the volcano where you can peer over the edge to see the bubbling ash-grey lake spitting scalding, reeking steam. From here you can hike along the craterâ€™s edge through the moon-like landscape. The ropeway is sometimes closed when the winds are right and blow toxic gases over the top of the ropeway. From the base of the ropeway, you can walk through the emerald-green grassland to the Aso Volcanic Museum. There is a video display in the museum connected to a camera mounted inside volcanic cone, and the camera is remote-controlled from the museum. The museum also has an excellent 17 minute movie of Aso-san and other volcanoes from around their world strutting their stuff.