To begin there are as with anything else in our world, certain rules, and to those rules, there are also certain exceptions.
In HTML, the opening tag, must also have a closure, which is usually a slash before the same tag enclosed in the opening.
The Exceptions to this are the horizontal rule, or HR, and the Break.. or the BR, which require no closure, and the P, or paragraph,
which again, does not require closing to operate correctly
