It's interesting to note that more than one film combines the Spanish Civil War with the secret life of children--as though the War itself were a child's game, played in the woods without parents to oversee, interfere, or protect; someone could get hurt. Pan's Labyrinth (2006) comes easily to mind, but so does another Guillermo del Toro picture, The Devil's Backbone (2001).
I don't know enough about Spanish cinema to explore this too far--but The Spirit of the Beehive seems far enough. At its core is the experience of movie going--the child's experience of seeing James Whale's Frankenstein--and if you're lucky you recall how mysterious the movies could be in your partial understanding, how dim but lasting in your memory. The film itself is beautiful to look at--or at least beautifully atmospheric--in the service of the attempt to film experience as memory. At times it reminded me of René Clément's Forbidden Games (1952), about France and World War II, as seen from down there among the table legs, the orphan and her temporary brother assembling the pet cemetery in the barn.
The Spirit of the Beehive has its barn as well; this one, though, seems something else than a memorial. Maybe a doorway of sorts--perhaps to adulthood, but certainly one of many portals leading to a miniature Gothic, an expanding place of secrets. As G. M. Hopkins says to the little girl, Margaret, in his poem "Spring and Fall," "What heart heard of, ghost guessed." Holy Ghost for him, I think; but in The Spirit of the Beehive, I'm not so sure.