A magnificent array of 1,400 drones illuminated the night sky of northwest China's Xi'an as the ancient city marks the 1,400th anniversary since it became the capital of the Tang Dynasty. The aircraft from Chinese drone maker Ehang Egret created formations such as gate tower and painting scroll characteristic of the city, forming beautiful 3D pictures that portray the golden age of Chang'an, the name Xi'an was called during the Tang Empire (618-917 CE).