Diving enthusiasts enjoy diving at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province, July 20, 2019. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)

    A tourist captures underwater images of a coral reef at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province, July 20, 2019. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)

    This underwater photo taken on July 20, 2019 shows a sea urchin taking cover amid corals at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)

    A diving coach checks status of corals at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province, July 20, 2019. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)

    A diving enthusiast enjoys diving at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province, July 20, 2019. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)

    Diving enthusiasts enjoy diving at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province, July 20, 2019. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)

    Tourists enjoy diving at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province, July 20, 2019. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)

    A diving coach searches for underwater litter at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province, July 20, 2019. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)

    This underwater photo taken on July 20, 2019 shows corals at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)

    Tourists enjoy diving at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province, July 20, 2019. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)

    This underwater photo taken on July 20, 2019 shows a shoal of fishes at the Boundary Island Tourist Attraction in Lingshui County, south China's Hainan Province. Boundary Island in south China's Hainan Province is hosting its first series of diving-themed activities from July 19 to 21, attracting diving enthusiasts, tourists, marine ecologists and diving equipment dealers worldwide. The PADI (Professional Association of Diving Instructors) Women Dive Day event was also held here on Saturday alongside the main events. (Xinhua/Yang Guanyu)