This is part six of the Bootstrap tutorial. In this video, we'll discuss nested rows and columns in Bootstrap. Bootstrap supports nested rows and columns, meaning that rows and columns can be placed inside an existing column. However, the fundamental principle remains the same - the total number of columns in the nested row should add up to twelve or fewer. It's important to note that we don't always have to use all twelve available columns. To understand nested rows and columns better, let's look at an example. Let's say we want to create a layout with a single row and two columns. The first column will be our main content area, and within that column, we want two rows - one for sidebar 1 and another for sidebar 2. Achieving this layout is easy with nested rows and columns. Here is the HTML structure needed for this layout: ```html