Silk was one of the most important trade goods. It was very valuable in Europe and merchants could carry it easily on their horses or camels. Silk was as valuable as gold and traders often used it as money to buy spices or other good. At this time people made silk into beautiful carpets, clothes, shoes, and pictures.
Trade good were not the only things that came along the Silk Road. Important new ideas and religions moved with people too. Buddhism travelled from India to China along the Silk Road. And people later brought ideas out of China-how to make paper and gunpowder, for example.
Modern tourists can now visit parts of the Silk Road by train, bus, or plane. But of course journeys at the time of Marco Polo were a lot slower. Merchants travelled about 40 kilometres on a very good day but under 20 kilometres on a bad day.