When the people there had enough Silk, they sold some, to merchants, who came from Other Places. The Silk was very valuable, because people who lived where there weren't silkworms could not get Silk.
The merchants went to Cathay to get the Silk, and they came back to the Middle East via a route they called the Silk Road. And they sold the Silk to people in Europe.
The Silk Road ran from Cathay in the East to the Mediterranean Sea. When you leave Cathay, you go West, and you come to a desert. You can try going through the desert, but that needs a Lot of water. Or, if you go South, there are mountains, and you can go along the edge of the desert , at the bottom of the mountains ,and there is some water there. But it takes longer.
At the far end of this desert, the mountains in the South curve up a bit, and the two roads rejoin each other. Then you have top cut through the mountains. This leads to high land where there is again a shortage of water, but not a desert. Here, though, there are places where there is water, and at these places, people have built little trading posts and wells and places to stay. You will find people here who will guide you (whereas the people in the desert might just take what you have, or so I have heard). If you take water with you from the wells, you can get from one place to the next one. They are called caravanserai.
As you go West, the land gets easier and there are better roads. There are also thieves, however (like in the Grym, but not as funny), because they know merchants go that way, and they look to rob them. That is why people group together, so that there are more of them than there are of the thieves. Eventually you get to a sea called the Caspian Sea and then another one called the Black Sea. If you turn left (that is, South) at the Black Sea and go along the shore, eventually you come to the great city of Constantinople, which is where the Silk Road ends, and the bazaars there buy the Silk.
There are Bears at either end of this Trade Route, but not in the desert or on the high plains.