I have created some vocabularies; there are further sub-categories in the categories. And I want to show the taxonomy hierarchy in an upper content block.

For example I have a vocabulary ‘a’ and having ‘x’, ’y’ and ‘z’ categories, ‘x’ also have ‘x1’, ’x2’, ‘x3’ and ‘x4’ categories and category ‘y’ having ‘y1’, ‘y2’, ‘y3’ and ‘y4’ same as other categories.

Also I have created a menu for ‘a’ of main vocabulary. I want, when a main category open then its subcategories should display in upper content block area, and if I clicked on any subcategory then its categories should list out in upper content block, and in content area all relative node should display.

I have been trying to find a simple way to do this, and it's not easily found.

I want to create a View (either a block or page, I would have application for both) that can list taxonomy terms in a given vocabulary.

Unfortunately, I can't figure out a good way to do this.

When I've tried, it's very inconsistent, and prints duplicates of the taxonomy terms (using node: distinct doesn't fix it).

Is there a way to do this? Thanks in advance..