Tourists visit the indoor ice-snow theme park at the Harbin Ice-Snow World in northeast China's Heilongjiang Province, June 3, 2019. The ice-snow theme park covers an area of 5,000 square meters. (Photos: Xinhua)

Photo taken on June 3, 2019 shows the scenery of the indoor ice-snow theme park at the Harbin Ice-Snow World in northeast China's Heilongjiang Province. The ice-snow theme park covers an area of 5,000 square meters.

Photo taken on June 3, 2019 shows the scenery of the indoor ice-snow theme park at the Harbin Ice-Snow World in northeast China's Heilongjiang Province. The ice-snow theme park covers an area of 5,000 square meters.

Tourists play on an ice-made slide at the indoor ice-snow theme park of the Harbin Ice-Snow World in northeast China's Heilongjiang Province, June 3, 2019. The ice-snow theme park covers an area of 5,000 square meters.

Tourists play on an ice-made slide at the indoor ice-snow theme park of the Harbin Ice-Snow World in northeast China's Heilongjiang Province, June 3, 2019. The ice-snow theme park covers an area of 5,000 square meters.

Tourists visit the indoor ice-snow theme park at the Harbin Ice-Snow World in northeast China's Heilongjiang Province, June 3, 2019. The ice-snow theme park covers an area of 5,000 square meters.