Like a wall, the Blue Mountains separate the coastal plains from the west. It took quite some time after the arrival of the first settlers to cross them and gain access to the agricultural and cattle areas in the west (with the usual consequences for the original inhabitants...)

To view the Blue Mountains from the west, take the road from Katoomba to the Jenolan Caves. On that road, there are some places where you have an excellent view over the Blue Mountains range, especially in the evening, when the range is lit by the sun from the west.