While learning Automata and computation theory independently, I made a realization I want to confirm.

Regular languages can all be created by taking elementary languages (languages made up of a single member of its alphabet) and performing closed operations in them, such as union, concat, and kleene star. This was clear to me from regular expressions.

Is this true? Is there any significance to this fact?

What about Context-free languages and other formal languages? Are there operations that can be performed on elementary languages to create all of them? Or is this a special property of regular languages only?