You guys have probably thought of it already, but I’m throwing it out there anyway. Since much of the game will be based on real past civilizations, maybe you could insert trivia (can be toggled on and off) during gameplay. For example, these can appear in a pop-up window when constructing farms or waterways. Afterwards, they can perhaps be further studied in a codex in the menu. I just think it would be a really cool way to learn world history.