Very "serious" companies create their own game engines (that I've heard). Although game like FarCry 3 was made with Dunia Engine which is just remake of Unreal Engine, which uses C++ programming. Very low, very powerful but also complicated.
Unreal Engine does have amazing graphics (go Google the latest ones), without even programming anything.
Define "very serious". Larger studios will likely have invested in building their own engines over the years or decades and reuse those.
Smaller and younger studios don't have that luxury and typically license an engine built by someone else, either one of those larger studios or a specialist company (think Unity as a popular example).
Those engines typically handle the graphics as well as the physics engine, and sometimes even part of the AI.
Under the hood of course the engine will then defer to the graphics engine of the operating system, using something like DirectX or OpenGL.