Ōkunoshima Poison Gas Island

Ōkunoshima is often marketed through rabbits, but its darker layer is the secret poison-gas programme and surviving military ruins. That contrast makes it an excellent haunt-map entry: charming surface, grim history beneath. Visitors should stay on public routes and treat derelict structures cautiously.

Public island and museum context. Derelict ruins can be unsafe; do not enter closed structures.