Blue Mountains

Declared in 1959, it is named for the bluish haze that usually hangs over its valleys, produced by the volatile oils its extensive eucalypt forests give off as they evaporate in the sun, an optical effect that scatters blue light selectively. It has been a UNESCO World Heritage Site since 2000 for preserving an exceptional diversity of eucalypts — more than 90 species within its boundaries, around 13% of all the species in the genus known worldwide. Its most celebrated rock formation, the Three Sisters, comes from a Gundungurra legend in which three sisters were turned to stone by a tribal sorcerer to keep them safe from a threat, and left petrified for ever in the landscape that the Echo Point lookout surveys.