The Blue Mountains is a rugged region west of Sydney in Australia’s New South Wales. Known for dramatic scenery, it encompasses steep cliffs, eucalyptus forests, waterfalls and villages dotted with guesthouses, galleries and gardens. Katoomba, a major town in the area, borders Blue Mountains National Park and its bushwalking trails. Echo Point affords views of the storied Three Sisters sandstone rock formation. The Blue Mountains get their name from the natural blue haze created by vast eucalypt forests in this World Heritage area. Tiny droplets of oil released from the trees mix with water vapour and sunlight to produce the distinctive colour.