User blog comment:Garr9988/New Mission/@comment-28082245-20170405001751

That really doesn't scream underground missile silo. I mean it could be one but it could just as well lead to a pit of lava, snakes or anything else. Without it being opened we really cant say for sure.

Oh maybe a bottomless ball pit, that might be an interesting artifact. One ball from a pit which just keeps multiplying. Just an idea.