Panda3D is a game engine originally created back in 1994 for several rides at Disney. It would later be used for their mmos and then open sourced where it's stil maintained to this day. You can use C++ or Python (it had smalltalk bindings at one point) and it's a lot of fun to use.

https://discourse.panda3d.org/t/panda3d-history/4398/3