[need] List categories inside page

Ok,
So I have a WordPress page that I made and I want a plugin that allows me to show categories of a certain depth on that page.

So lets say I have a category called ‘Pop music’ and subcategories like “Britney Spears”, “50 Cent” etc

I would like to show all subcategories of the ‘pop music’ category on a page I create called ‘Pop music’.

I have searched for plugins and cannot find any, I have looked for code but cannot find anything.

Any idea?