Previously our favorite was "Stephen Biesty's Man-of-War," which detailed life on a Napoleonic-era battleship. That one provided such good information that even an adult reading an old Horatio Hornblower novel could use it as a reference book.
Likewise, "Rome" depicts the main buildings and neighborhoods of Rome, maintaining a narrative about a young boy of noble family, Titus, as he investigates his native city.
An absolute must for any child or adult interested in ancient history or trying to become interested!