In nanos world, all interactions are made through a Class or a Static Class. That means 99% of things you would do needs an Object/Table reference to be done. With that in mind, this page will list all nanos world Objects which already exists and/or is spawned by default and can be accessed from anywhere.
For example, if you want to interact with World (move the sun, set it rain, etc), you will need the
World Static Class:
World is a Static Class and exists by default, i.e. you do not need (or can) spawn World entities. P.S.: the code above is client-only.