Earlier quoted context omitted.
I fondly remember NovaLogic's Comanche series. While it isn't of the 'world building' genre, its voxel engine was very impressive for its time: http://en.wikipedia.org/wiki/Comanche_series Also interesting (historically) is 'Rescue on Fractalus'. Not just for its cheesy name, but also due to its reliance on fractals to draw 3D mountain sceneries: http://en.wikipedia.org/wiki/Rescue_on_Fractalus ! Edit: videos of both…
Rescue on Fractalus had one of the most genuinely terrifying game moments of my 'career'. I won't spoil it here, but you can probably guess what it was from the wikipedia page.
http://www.youtube.com/watch?v=M8opv5u9nf0
First time (as a kid) was shocking...