About 2 hours drive west of Sydney lie the Blue Mountains. A blue haze over this area is said to be caused by the gases from the eucalyptus oil in the leaves of the very Australian gum trees. Much of the area is National Park and so a conservation area. Many of the ridges provide wonderful views over the vast valleys and drop-off points for countless waterfalls. During low rainfall these waterfalls are reduced to trickles and at other times they thunder down the sandstone cliffs.
The bush (australian forest) areas closest to the main towns provide popular walking tracks and also extensive hiking opportunities. Parts of Katoomba have become extremely popular with day-tripper tourists who are happy to snap away at the first sight of the Three Sisters (rock formations) and then quickly load up on fluffy koala toys from the souvenir stands. Other more adventurous types go mountain-biking, caving, canyoning, abseiling and rock-climbing in the ravines, gorges and river valleys of this beautiful area.