Science Fiction Books/Short story collection
When I was in school (1990's), I borrowed a collection of science fiction short stories from the library that included "Who Goes There?" I can't remember if it was Analog, or Year's Best Science Fiction or another collection. I vaguely remember some other story about a child who had a whole civilization in (a box?) in his bedroom. I think his sibling wanted to damage it. Does that collection or that story ring a bell? I'd love to get the collection but if not, at least that other story. I wish I remembered more!
It is hard to tell which collection or anthology you read, BUT, it could have been Adventures in Time and Space, edited by Raymond J. Healy and J. Francis McComas.
Here is a link to the entry in the Internet Science Fiction Database for that book
There was also a little Dell paperback, called "Who Goes There and Other Stories", and it was one of the three stories in that book