Other things that often weighed heavily on a camel's back included water flasks and, more importantly, bundles of silk that, once sold in Constantinople, could fetch hundreds of times their cost price in China.

But that is not all, says Li Yongping of the Gansu Provincial Museum, who compares the trading caravans with an itinerant circus. The ancient Silk Road cut through Gansu during its westward extension.

"That circus was stuffed by a big variety of animals - monkeys and eagles, peacocks and ostriches, lions and leopards, and possibly elephants and rhinos," Li says.

After a journey that must have been extremely demanding, if not costly in lives, most of these rare animals ended up in the private gardens or enclosures of the aristocrats, to be looked at by a privileged few. Artistic renderings also appeared, often in the burial chambers of these men who had gone to great lengths to make sure that their afterlife would be lived in the fashion to which they had become accustomed.