Visitors take photos in the indoor ice-snow theme park of Harbin Ice-Snow World in Harbin, capital of northeast China's Heilongjiang Province, July 28, 2019. The indoor ice-snow theme park of Harbin Ice-Snow World, with from minus 5 to minus 8 degrees Celsius inside, has attracted a lot of visitors to enjoy the cool place during summer time. (Xinhua/Wang Jianwei)

A woman plays in the indoor ice-snow theme park of Harbin Ice-Snow World in Harbin, capital of northeast China's Heilongjiang Province, July 28, 2019. The indoor ice-snow theme park of Harbin Ice-Snow World, with from minus 5 to minus 8 degrees Celsius inside, has attracted a lot of visitors to enjoy the cool place during summer time. (Xinhua/Wang Jianwei)

People visit the indoor ice-snow theme park of Harbin Ice-Snow World in Harbin, capital of northeast China's Heilongjiang Province, July 28, 2019. The indoor ice-snow theme park of Harbin Ice-Snow World, with from minus 5 to minus 8 degrees Celsius inside, has attracted a lot of visitors to enjoy the cool place during summer time. (Xinhua/Wang Jianwei)

Visitors play on the ice slide in the indoor ice-snow theme park of Harbin Ice-Snow World in Harbin, capital of northeast China's Heilongjiang Province, July 28, 2019. The indoor ice-snow theme park of Harbin Ice-Snow World, with from minus 5 to minus 8 degrees Celsius inside, has attracted a lot of visitors to enjoy the cool place during summer time. (Xinhua/Wang Jianwei)