Some of the 90s era educational games were pretty cool:

• The Dr. Brain series
• Logic Quest 3D - An edutainment FPS set in a medieval world with logic programming and voice acting. The controls were terrible.
• Stowawy! - Very minimal gameplay, but a great experience. I would kill for a 4K remaster.

Pharaoh/Cleopatra had lots of relatively in-depth explanatory text about life in ancient Egypt, but I don't know if it qualifies as an educational game.