Its not really a toughest prison thing but you know what show is really good is "Locked up Abroad" its on the national geographic station.
Its about these real life people that have been locked up in different countries for different things sometimes nothing at all and they tell there story.
Most episodes I have seen are pretty damn good.
I just watched one this past Wed about Indonesia the guy was wrongly accused of smuggling drugs into country and was sentenced to life in there prison he tried escaping like three of four times. I'm telling you check it out.