If you're visiting Nanjing, you absolutely must check out the Nanjing Museum. It's a huge place with tons of exhibits and a fantastic experience. The museum is structured as one building with six galleries: a history gallery, a special exhibition gallery, a digital gallery, an art gallery, an intangible cultural heritage gallery, and a Republican-era gallery. Even a cursory glance could take a whole day to explore. The audio guides are very user-friendly, with several types available for adults, students, and children, catering to different age groups. The replica Republican-era street below is quite immersive. There are also many souvenirs available; I bought these building block fridge magnets, which are quite suitable for kids and also have a nice souvenir value.