Photo taken on July 11, 2017 shows tourists visiting the Qixing Lake Scenic Area of the Saihanba State Forest Park in Weichang Man and Mongolian Autonomous County of Chengde City, one "natural oxygen bar," in north China's Hebei Province. As more and more Chinese people are choosing to visit places that have fresh air, thick forests and are rich in negative ions, ecotourism becomes a fresh favoured choice across the country. According to a report by the China Meteorological Service Association, trips to the regions granted as "natural oxygen bars" by the association surged over 200 percent year on year in 2018. (Xinhua/Wang Xiao)