In Sydney I joined my tour group and we travelled to the Blue Mountains. Sometimes when the sun hits the oils in the eucalyptus trees, the trees appear to be blue, so when the settlers first saw them they gave them the appropriate name. This was an amazing national park, and we hiked up and down the mountains, saw some waterfalls, etc. The next day we drove down to the Jenolan Caves, which were limestone caves in the middle of a mountain in the middle of nowhere.