What is the fine-grained topic of the following text: In the "Beijing West Gravitational Off-Road Park" in Tongzhou, although the scope of the competition only covers the Beijing-Tianjin-Hebei region, I feel that friends from Beijing Station who love cross-country sports in North China have gone, and can see Xinjiang, Inner Mongolia, and Shanxi. Only return the topic.
The fine-grained topic of the text is a cross-country sports competition in Beijing West Gravitational Off-Road Park, Tongzhou.