Aerial photo taken on June 18, 2020 shows an isle of Heilongjiang Taiyangdao National Wetland Park in Harbin, northeast China's Heilongjiang Province. (Xinhua/Wang Jianwei)

Aerial photo taken on June 18, 2020 shows a view of Heilongjiang Taiyangdao National Wetland Park in Harbin, northeast China's Heilongjiang Province. (Xinhua/Wang Jianwei)

Aerial photo taken on June 18, 2020 shows a view of Heilongjiang Taiyangdao National Wetland Park in Harbin, northeast China's Heilongjiang Province. (Xinhua/Wang Jianwei)

Aerial photo taken on June 18, 2020 shows a view of Heilongjiang Taiyangdao National Wetland Park in Harbin, northeast China's Heilongjiang Province. (Xinhua/Wang Jianwei)

Aerial photo taken on June 18, 2020 shows a view of Heilongjiang Taiyangdao National Wetland Park in Harbin, northeast China's Heilongjiang Province. (Xinhua/Wang Jianwei)