The National Museum of Galle, located in the oldest Dutch building in Galle Fort, is a cool spot to check out some history. It opened in 1986 and has exhibits from the Portuguese, Dutch, and British periods. You can see things like turtle shell jewelry, and Dutch furniture, and even learn about trade relations between China and Sri Lanka. It's a great place to explore if you're into that kind of thing!
Note: It's temporarily closed for renovation