Dog Breeds: Old vs New, Working vs Show- with many pictures

[Mutt Farm]

How are they used in prisons? Do they guard it to prevent people escaping, like around the building as a sort of modern-day moat?
I've heard the dogs described as "savage" many times. They remind me of lions or some other wild predator.
Do you remember what the special was called? I would like to watch it if you know.

and @cassie I found part of what I saw on YouTube. This wasn't the program I watched, but this footage was in it.