I'm sure this is not what you had in mind, but my kids (who are 4 and 5) have learned absolutely amazing amounts from the Magic Treehouse books by Mary Pope Osborne. They are not exactly scholarly, nor are they great literature, but my kids know a lot about China, the Amazon, the San Francisco earthquake, Leonardo da Vinci, etc., from reading Jack and Annie books. They have served as a springboard for more in-depth explorations of many topics, too. They also have "research guides" to a lot of the books, which are non-fiction.
You might also be interested in the
If You series or the
You Wouldn't Want to Be series.
We have found that we learn a lot from and enjoy most those books that are just fun to read and aren't necessarily a "curriculum-type" book or series. Things like American Girl, Magic Treehouse, the two series I linked above, and just whatever random historical fiction novels or nonfiction children's books we find at the library capture my kids' interest and attention. We don't learn history and geography in any sort of sequential way (we're unschoolers) and my kids leap from interest to interest as interest strikes them.
dm