Xira Genesis is an online RPG/Sandbox Game with a turn-based battle system where you can gain skills and abilities that let you modify almost every detail of your world!
The current process of building a new area in game.
First you terraform a new exit to the current area. You walk into the new "void" area and terraform the landscape to "wilderness". Then you go about building whatever you want in the area. Its a very simple process that will not change much before release. Though you will have to clear the "void" area out of special void monsters before you terraform it, and you will also be able to summon creatures/NPCs to your new areas. These things are still in development.