Bronze figure of a horse, Eastern Han dynasty, 2nd century C.E., Excavated from a tomb in Letai, Wuwei county, Gansu, H. 36.5 cm., Gansu Provincial Museum. Source: Asia Society

Born in the mountains of Kazakhstan, the apple hitched a ride to the rest of the world in the packs of humans and stomachs of animals traveling on the Silk Road. Humans picked up the delicious fruit to eat along the way, dropping the cores that house the seeds and all future apples.

But animals are an essential part of the story of the Silk Road. Horses, among other animals, played a key role, providing both milk for local use and transportation for the development of international relations and trade. The clever apple evolved to have smooth, tear-dropped shaped seeds perfectly proportioned to pass intact through the intestinal tract of a horse. In the belly of a horse, an apple could travel 40 or 50 miles a day, gaining tremendous ground in its takeover of the temperate world.