A sightseeing train trundles through the Greater Khingan Mountainous area in Hulun Buir,Inner Mongolia autonomous region is seen in this photo taken on Dec 21,2015. The Greater Khingan mountains are a volcanic mountain range in Northeast China. They stretch across a distance of over 1,200 km from the northeast to the southwest,with a width of 200-300 km. The cold temperate continental monsoon climate makes the area a colorful place during all seasons of the year.[Photo/Xinhua]