An aerial photo shows the Songhua River beginning to freeze as temperature dropped to around -15 C recently in Harbin, Heilongjiang province. [Photo by Zhao Tianhua/For chinadaily.com.cn]

As temperatures dropped to around -15 C recently in Harbin, Heilongjiang province, the Songhua River in the city began to freeze over.

Huge crystal ice floes on the river rumble audibly, and the spectacular scene attracts many residents and photographers.

Local officials reminded residents not to get close to the river to avoid danger.