Zhu Jie, who directed several of the episodes, used stop-motion animation techniques to unfold the backdrop stories about The Gold Crown With an Eagle Perched on Top, the subject of the first episode of the second season.

Unearthed in the Inner Mongolian autonomous region in 1972, the centuries-old symbol of power was buried with a nomadic tribal ruler in China's northern prairies. Weighing 1,394 grams, it is the only crown of its kind ever to be discovered by archaeologists.

For the hundreds of years between the Qin and Han dynasties, emperors in the Central Plains fought wars with the northern tribes, causing innumerable deaths and injuries. Unwilling to recreate this dark chapter in history in a realistic, bloody way, Zhu asked a friend at a fine arts school to create puppets to shoot scenes about the conflict in the form of an animated short tale.

Up to 20 centimeters tall, the puppets were painted like nomadic warriors.

"It took us more than two months to finish the episode, making it the longest one I've made for the series," says Zhu.

A fan of Chinese culture, Zhu adds that he has been amazed by the depth of the ancient Chinese civilization during the making of the series. One of the items that impressed him the most was an ancient plain silk gauze garment, the subject of the 17th episode. Weighing just 48 grams, the light and transparent robe was discovered in Changsha's Mawangdui Tombs, which dates back to the Western Han Dynasty (206 BC-AD 24). The garment was buried with Xin Zhui, the wife of a prime minister of the Changsha Kingdom, a vassal state under the Han court.

"I was told the garment could fit into a matchbox. Experts nowadays have spent many years trying to make a replica of the robe. It's incredible to imagine that Chinese craftsmen had mastered such intricate silk-weaving skills more than 2,000 years ago," says Zhu.

The documentary is set for international release. According to Xu, the first season has already been translated into eight languages, including English, French, Spanish, Italian and German.