Five black swan cygnets play with their parents in the lake at the Old Summer Palace in Beijing on Thursday, December 6, 2018.

Five black swan cygnets play with their parents in the lake at the Old Summer Palace in Beijing on Thursday, December 6, 2018.

Five black swan cygnets play with their parents in the lake at the Old Summer Palace in Beijing on Thursday, December 6, 2018.

Five black swan cygnets play with their parents in the lake at the Old Summer Palace in Beijing on Thursday, December 6, 2018. (Photos: VCG)