Twinity is the most creative virtual world ever made.
In Twinity you can make friends easily , and have your free starter
In Twinity you can buy virtual land without paying monthly rent.
Is easy to upload some models that everyone can make with Trimble
Sketchup ( free 3D model program ). That is very handy, because you
can create castles , cathedrals, and everything you want with detail
and your own textures.
And this is a huge advantage if you like to learn about 3D modeling.