Second Life Geography - An Overview

Pull the map slider all the way to the left, and you will get a satellite view of Second Life.

World Map 07-28-2019

What you are seeing is sometimes called "The Grid", which is a spatial representation of all the land, water, and void ocean in Second Life.

Some definitions:

Region - an area 256 by 256 meters.
Agni - another word for The Grid. The testing grid is called Aditi*.
Void Ocean - the 'big nothing' between places. You cannot move through it - you will have to teleport over it.
Land - a place with a physical surface.
Water - a physical surface, but covered with water.
Sky - the accessible area over land or water. A lot of people build and live there in what are called "skyboxes".
Continent - usually refers to a mass of 30 or more regions connected to each other in such a way that you can move between the regions without teleporting.
Subcontinent - is part of a larger continent that has its own name. An example are Nautilus and                       Satori. You can get from Nautilus to Satori now without teleporting, but in the past they were separated by Void Ocean. As more and more continents become connected (Thank you, Moles) subcontinents will probably become more common.
'Microcontinents', 'sim clusters', and 'sim groups' are just smaller groups of regions - but I'm not going into counting the regions of each one. 
'Isolated' or 'unassociated sims' are regions that cannot be grouped into other structures.



Question: This is boring, and why should I care?
Answer:  I'm guessing that when you go on vacation, you don't just sit in the airport after you get to your destination. In my opinion, too many new residents just hang around the first place they land in after they have finished minimal basic training, and then complain that there is nothing to do.  If you want to explore, you need to know where you can go and what you can do there. Most continents are public access, but a lot of the smaller structures are not.
(more later).

*You can't see it here, because it is in another dimension.

A brief history of how Second Life was built and is continually evolved:

See the Second Life Wiki for early history information.

Here is the first map of Second Life I could find. You can see that some of these regions still exist. Yadni Monde used to have a wall of historical maps in his Junkyard, but that is gone. Currently there is an excellent exhibit of maps at New Kadath Lighthouse Gallery.