I guess the Oregon Trail. I remember first playing it in school. It plays like a game but teaches you of the routes people took to get to Oregon, the hardships, the history of the landmarks.
I know it's not really 'educational' but at least I consider them as such and I'd rather vote for both Sim City and the original Civilization. SC taught how to handle a basic budget, basic economics, city development, planning, and how to handle a crisis situation too. Civilization taught the benefits of war and peace, development, expansion, budgets, resource allocation and distribution all under the hood of a big fat history lesson because each Civilzation had the basics of them displayed but it also gave a little history lesson summary of every tech from numbers and letters to space parts and nuclear power.