Lively is organized in Worlds. This web page is a world. All visible morphs are part of this world.
The world is the initial morph. That is, as in Smalltalk, all morphs have owner, except for the world. See for yourself:
this.owner<lively.morphic.Box#1069 - TutorialArea>
Besides containing all visible morphs, the world also provides all kinds of functionality. Right-click on the light-gray background to see the World menu! There you can find tools, parts and the PartsBin and you can save the world in its current state.
Also, the world offers lots of functions outside of menus. For example, you can get a handle on Morphs by their name from the world. Try:
$world.alertOK("Hello. I'm the world!")null