It was said that a man could walk from one end of the Mongol Empire to the other with a gold plate on his head without ever fearing being robbed. Two, the Mongols increased communication through Eurasia by developing this pony express-like system of way stations with horses and riders that could quickly relay information. It was called the Yom system, and it also included these amazing bronze passports, which facilitated travel. Three, another thing that traveled along Mongol trade routes was cuisine. For example, it was because of the Mongols that rice became a staple of the Persian diet, which I mention entirely because I happen to like Persian food. Four, the Mongols forcibly relocated people who were useful to them, like artists and musicians and especially administrators. As you can imagine, the Mongols weren't much for administrative tasks, like keeping records, so they found people who were good at that stuff and just moved them around the empire.