View from Echo Point towards south to the Three Sisters Meehni, Wimlah, and Gunnedoo (left side), and to Mt. Solitary (950 m) in the centre of the image. The Blue Mountains represent a section of the Great Dividing Range. Essentially, they consist in a large sandstone plateau with steep or even vertical escarpments leading down to deeply incised valleys and gorges. The Blue Mountains were declared a UNESCO World Heritage Site in 2000.