From the BBC World Service: Have you ever wondered where your festive Christmas lights, ornaments, and toys all come from? Well, there's a good chance they originate in the Chinese city of Yiwu. It's home to a major the world's largest wholesale market and produces more than half of the world's Christmas decor. This Christmas morning, we'll take a trip to the city and hear how it's being affected by the latest U.S. tariffs