Single Player>Survival>Start Game. The loading screen dissipates.
A meshed virtual world stretches out before you, complete with mountains, oceans, ravines, trees, animals, rocks, minerals. Tabula rasa.
But: not really - the subsurface logic of the land is based on a prescribed algorithm. A set of finite axioms plans its contours, and produces an environment which mimics the geodesic possibilities seen on our own Earth.
It is a simulation of nature, when millions of years of development are preprogrammed to take place in a span of seconds, while the loading screen works its magic.