![More than 500 drones rehearse for a light show to celebrate the opening of the China International Big Data Industry Expo 2019 in Guiyang, Southwest China\'s Guizhou Province, May 24, 2019. The four-day expo attracted 448 enterprises from 59 countries and regions, according to the organizing committee. (Photo: China News Service/Yu Jiayang)](http://www.ecns.cn/hd/2019/05/27/c197c439e182460e9c39d3710c7a2773.jpg)
More than 500 drones rehearse for a light show to celebrate the opening of the China International Big Data Industry Expo 2019 in Guiyang, Southwest China's Guizhou Province, May 24, 2019. The four-day expo attracted 448 enterprises from 59 countries and regions, according to the organizing committee. (Photo: China News Service/Yu Jiayang)
![More than 500 drones rehearse for a light show to celebrate the opening of the China International Big Data Industry Expo 2019 in Guiyang, Southwest China\'s Guizhou Province, May 24, 2019. The four-day expo attracted 448 enterprises from 59 countries and regions, according to the organizing committee. (Photo: China News Service/Yu Jiayang)](http://www.ecns.cn/hd/2019/05/27/b3f0dce58cfb4139a3b8e940fdd1a7b5.jpg)
More than 500 drones rehearse for a light show to celebrate the opening of the China International Big Data Industry Expo 2019 in Guiyang, Southwest China's Guizhou Province, May 24, 2019. The four-day expo attracted 448 enterprises from 59 countries and regions, according to the organizing committee. (Photo: China News Service/Yu Jiayang)
![More than 500 drones rehearse for a light show to celebrate the opening of the China International Big Data Industry Expo 2019 in Guiyang, Southwest China\'s Guizhou Province, May 24, 2019. The four-day expo attracted 448 enterprises from 59 countries and regions, according to the organizing committee. (Photo: China News Service/Yu Jiayang)](http://www.ecns.cn/hd/2019/05/27/6b5520c28b1c4eda82a953a7f849be42.jpg)
More than 500 drones rehearse for a light show to celebrate the opening of the China International Big Data Industry Expo 2019 in Guiyang, Southwest China's Guizhou Province, May 24, 2019. The four-day expo attracted 448 enterprises from 59 countries and regions, according to the organizing committee. (Photo: China News Service/Yu Jiayang)