Gaia

Gaia is the world which human beings inhabit, and you probably do too, unless you are an alien, in which case you will not be able to read this anyway, so STOP CLOGGING MY BANDWIDTH. Its appearance on the surface is a rubbish dump like the one shown, with human beings crawling over the heaps of plastic bags to get to work.

Position in space
Gaia is the third rock from the sun in the Sol system (unless there are comets around, in which case you may end up here or here). Sol is located in the Orion Arm of the Milky Way in the Local Group of the Local Supercluster of The Universe of Reality.

Geography
Gaia is divided into 4 landmasses and many small islands. The larger landmasses are split into smaller pieces, called "continents", while the smaller landmasses are continents on their own. Islands are randomly attributed to a nearby continent, even if it is not the nearest.

Here is a list of the landmasses of the world (more information lies in their specific articles):

Euraso-Africa

America

Antarctica

Oceania

Here is a list of the continents of the world (yet more information lies on their specific pages)

Europe

Asia

Africa

North America

South America

Antarctica

Oceania

Here is a list of the islands of the world...oh, why bother? Lists of islands can be found in their respective continents.

If you want more information, go and ask the United Nations, or, if you do not want hear a load of self-righteous garbage, just look round all the articles offered...