The latest wildfire in Yosemite National Park in the U.S. has expanded from 250 to 1,600 acres as more than 400 firefighters struggle to contain it. The park's famed giant sequoia grove has survived its first wildfire in more than a century, thanks to regular efforts to burn the undergrowth beneath the towering trees. An aerial firefighting plane was also sent to drop retardant near the grove. The wildfire that started near a trail has been 22% contained and is now moving away from the grove.