This is our top-level category. (Looking at it another way, it is our root category!)
Ideally, every other category should be a subcategory of at least one other, and every article should be in at least one category; many will fit well into two (eg location and subject-matter). A full list of existing categories can be found at Special:Categories.
This category has the following 10 subcategories, out of 10 total.
Pages in category "Index"
The following 10 pages are in this category, out of 10 total.