A cliff in the stunning Blue Mountains, NSW, Australia. I had heard of them, but never thought much about their name. I was surprised to learn that the air had a blue tinge, at least on the cloudy day I was there. It's caused by the eucalyptus oil mist in the air, which I could smell. The trees themselves were bluish-gray. A vast forest of eucalyptus, I suppose of several varieties, an unusual and beautiful place.