Some Jews supposedly journeyed to Ethiopia -- they have been known to get around. I'm open to the possibility that the real Ark is in there, old as it may be. I'm also open to the possibility that there's a mock-up in there, and that its guards honestly believe it's the real thing. It seems less likely that it's just an empty room, because in that case it seems to me some devastated young guardian, sometime through the generations, would have spilled the beans that there wasn't this specific object in a specific place.