In Sydney, Australia, health officials are warning young and elderly residents and people with respiratory illness to stay indoors and avoid exercise, as a thick blanket of smoke from unprecedented wildfires settled over the city of 5 million people. The out-of-control fires have raged for weeks as much of the continent is baked by a searing heat wave, with the city of Melbourne on Wednesday matching a November temperature record. Highs in parts of New South Wales have topped 110 degrees Fahrenheit this week. More fires are raging in Victoria and Queensland states.