It's fun to watch a baseball game, but did you ever wonder where the balls come from? Read on, and you'll find out.

In Dushan county of Guizhou province, more than 10,000 baseballs roll off the production line of a factory every day and are exported to Europe and the United States.

To make a professional-grade baseball, quality control is crucial. In the workshop of Dushan Runyang Sports Equipment Co, experienced operators strictly control the weight of each ball — between 142 and 147 grams.