Fireworks explode over the sky in south China's Macao, Dec. 22, 2019. Macao and its neighboring city Zhuhai jointly held a firework show to celebrate the 20th anniversary of Macao's return to the motherland on Sunday. (Photos: Xinhua)

Fireworks explode over the sky in south China's Macao, Dec. 22, 2019. Macao and its neighboring city Zhuhai jointly held a firework show to celebrate the 20th anniversary of Macao's return to the motherland on Sunday.

Fireworks explode over the sky in south China's Macao, Dec. 22, 2019. Macao and its neighboring city Zhuhai jointly held a firework show to celebrate the 20th anniversary of Macao's return to the motherland on Sunday.

Fireworks explode over the sky in south China's Macao, Dec. 22, 2019. Macao and its neighboring city Zhuhai jointly held a firework show to celebrate the 20th anniversary of Macao's return to the motherland on Sunday.

Fireworks explode over the sky in south China's Macao, Dec. 22, 2019. Macao and its neighboring city Zhuhai jointly held a firework show to celebrate the 20th anniversary of Macao's return to the motherland on Sunday.

Fireworks explode over the sky in south China's Macao, Dec. 22, 2019. Macao and its neighboring city Zhuhai jointly held a firework show to celebrate the 20th anniversary of Macao's return to the motherland on Sunday.

Fireworks explode over the sky in south China's Macao, Dec. 22, 2019. Macao and its neighboring city Zhuhai jointly held a firework show to celebrate the 20th anniversary of Macao's return to the motherland on Sunday.

Fireworks explode over the sky in south China's Macao, Dec. 22, 2019. Macao and its neighboring city Zhuhai jointly held a firework show to celebrate the 20th anniversary of Macao's return to the motherland on Sunday.