Too bad that the only real option to play it these days is still 800x600 on a Win98 VM. If GOG ever offers a version that works on modern operating systems, it will be a "Shut up and take my money" moment for me.
Someday, I want to build a medieval/ancient set game with the same general mechanics...
Blizzard is never going to give away their back catalog (they'd sell it themselves). Neither is Valve. Nor, most likely, is EA, with their awful Origin service.
Then there are all of the newer games that you can find anywhere... Obviously, they've got to make money and focus on what pays the bills, but it makes me happier when I see abandonware and unavailable games get legitimate releases on there, compared to when its something already on Steam.
I remember loving Microsoft Dinosaurs—a wikipedia search for it redirects to a list including that and a bunch of similar looking titles under the Microsoft Home label—and Explorers of the New World, which even the Internet apparently barely remembers judging from the google results. They'd be OK for a 1st grader but those weren't even games, really.
Main issue is they're all old. A few are hard to run. Some are only available on used CDs. Not sure how they'd keep a modern kid's attention. I gather there are some good games like this on tablets and such, but my kids aren't quite old enough for that stuff yet, so I can't recommend any.
Side note: I'm pretty sure playing Doom, Dark Forces, Wolf3D, and other FPS games with confusing maps from young age is ~20% responsible for my wicked-high scores on spatial reasoning tests (Building lego sets from the instructions can be credited with the other ~80%) so, there's that.
[1] https://en.wikipedia.org/wiki/Munchers
[EDIT] wold3d -> wolf3d
If you haven't played "Civil War Generals 2: Grant, Lee, Sherman" you should. It's Robert E. Lee: Civil War General but with the brokenness fixed—there's a victory point system that's in part based on locations held, which keeps you from just turtling on the nearest high ground and waiting for the enemy to come into cannon range—and a much larger campaign. It's kind of tricky to run these days, and is a bit unstable even under ideal conditions. Best solution may involve a Win98se VM. :-/
The Encarta game was awesome. I'd forgotten about it. Thanks for the memory.