A short drive up from Sydney, the mountains encompass a large area of inland New South Wales. I remember how the mountains seemed to drop off, as opposed to rising up, and this would make sense considering they are a sandstone plateau with gorges being carved out of it.
The aboriginal legend is a Gundungurra creation story where the Dreamtime half-fish half-reptile creatures Mirigan and Garangatch fought a large battle, scarring the landscape. Many areas of archaeological importance are in the area (22,000 years old), with the rock shelter Red Hands Cave having ancient hand stencils and other areas having grinding stones and carved animal track images.
They were called the blue mountains because of the appearance from a distance, believed to be caused by mie scattering combined with ultraviolet radiation, and the terpenoids emitted by the many eucalyptus trees (though I admit I don't really know what that means!).