On a rainy afternoon in Halong, one of the best things to do is to visit the Quang Ninh Museum. This museum showcases the rich history and culture of the region, with exhibits ranging from ancient artifacts to contemporary art. You can learn about the geological formation of Halong Bay, the traditional customs of the local people, and the impact of coal mining on the area. The museum also offers interactive displays and multimedia presentations, making it an engaging and educational experience for visitors of all ages.