They are known as AAA games. They require a lot of money, a lot of time, and a lot of developers to make. Basically, everything you see -trees, cars , people etc are created using a 3d software such as 3dsmax, maya or blender. Then they use something known as a game engine to define properties (for eg, make the car go forward when the user presses 'w'). Many games use a game engine exclusively created for it. So its art+code=game. If you are interested in making 3d games maybe you should try panda3d. Its a free game engine for python and its easy enough. http://www.panda3d.org/ : for the game engine And I'm sure there are a lot of python tutorials flying around. Python is the easiest thing you can learn (other than html, of course!) And www.mygamefast.com has one of the best tutorials ever. It takes a lot of effort and a lot of people to build games like GTA and Warcraft and Simcity. But there are a lot of one-man indie games around that are quite impressive.
The best way to know something is to try it out. All the best.
EDIT: The Unity game engine is probably the best way to start these days. It lets you write your game once and then compile it to run on many different platforms.