We learn from marco polo that , in the administration of his empire , kublai khan made use of a fast and simple message system. Horse riders spaced every 40 kilometers allowed message to cover 500 kilometers a day. As soon as one horse had run 40 kilometers, the next horse would run the next 40 kilometers ,and so on. Marco also learned the secret of asbestos cloth, which is made from a mineral and doesn't catch fire. paper money also took him by surprise , since it was not yet in use in the west at that time. Homes wrer heated with " black stones.....which burn like logs. "Theose stones were coal - unknown in most of europe- and were so plentiful that many people had a hot bath three times a week.