Install and activate the Views Tree module.
Add a new 'Taxonomy Terms' view. (Choose the vocabulary or 'All').
Add a relationship to Taxonomy Term:Parent Term. Do NOT set this relationship as required.
Add two fields for Taxonomy Term:Term ID.
The first label as Main Term ID, and exclude from display. This one does not use the relationship.
The second label as Pareent Term ID and exclude from display. This one Does use the relationship.
Add any other fields you wish to include (Name, Description etc) and style as you wish.
Change the view format from Unformatted List to Tree (Adjacency model), and under settings, set the Main field to Main Term ID and the Parent field to Parent Term ID.
Create a page display, give it a path, and save the view. Go to the path and look at your taxonomy tree. (The tree styling sometimes does not display in the live preview, particularly if you use Seven as an admin theme.)