Went to see Lava Tubes. They look like tunnels that run under the rainforest. They are actually hollowed out lava flows. The vegetation has regenerated on the old lava flows over thousands of years. And will continue to do so on the newer lava flows, there is evidence of this all over the park.
There are steam vents all over the park, where fissures have formed, rain water seeps in and condenses when it meets the hot rocks below the surface. The steam is then released and it appears as though the trees are burning. There is a smell of sulphur all over the park, quite over powering in places.
The Sulphur Banks where the walls of the caldera have collapsed have formed yellow crystals on the rocks. You have to stay on the boardwalks because the crust is so thin it might collapse under your weight and the temperature just below the surface is 150C. Not pleasant!