Aerial photo taken on Sept. 28, 2017 shows agricultural machinery working in fields at the Sanjiang Plain, northeast China's Heilongjiang Province. Located in northeast China, Heilongjiang Province is widely-known for its distinct seasons and its endeavor to promote ecological development, especially in the Greater and Lesser Khingan Mountains. The forest area in the Khingan Mountains, which is regarded as an important forest eco-function zone and a reserve of strategic significance for timber resources in China, plays an irreplaceable role in maintaining national ecological security and long-term wood supply. Based on its vast woodland and rich forest resources, Heilongjiang in recent years has been committed to developing eco-tourism in forest area to be a pillar industry, a move to diversify its tourism forms and provide high-quality services. The 2019 Beijing International Horticultural Exhibition kicked off its "Heilongjiang Day" event on Thursday. By touring the Heilongjiang Garden, visitors can catch a glimpse of Heilongjiang, a beautiful land of varied topography that is home to abundant biological species and incubates unique cultural customs. (Xinhua/Wang Jianwei)