Trees are covered with glassy hoar frost, known as Wusong rime, beside the Songhua River in Jilin city, northeast China's Jilin Province, November 28, 2006. As a unique natural phenomenon in Jilin in the winter, Wusong emerges on trees when the steaming vapor from the Songhua River hits the freezing air which could be about minus thirty degrees centigrade. (newsphoto)