Kabutogani Museum is Kasaoka's most distinctive mainland sight. It focuses on horseshoe crabs, the "living fossils" that give the museum its Japanese name, and explains their biology, habitat, and local connection to the coast.
The adjoining Dinosaur Park is playful rather than scholarly, but it makes the stop easier for families. For everyone else, the point is the horseshoe crab story, which gives Kasaoka a natural-history hook few Japanese port towns can claim.