key. critics say that has been our countries approach to crime for far too long. the the question whether mass incarceration is keeping us any safer. and, what lengthy prison terms mean for many of the more than 2 million americans behind bars. lester holt spent three days in one of the nation's toughest penitentiary's, and this is what he witnessed. here's his special report, life inside. >> life at angola prison isn't what you might imagine. the vast majority live just like this. more than 80 men in open dorms sleeping on bunk beds. but i'll be staying on a unit next to death row for high risk offenders, or in my case, a high profile guest. >> we're going to go down the tier here. >> my home for the next 2 nights will be on a tier called ccr or closed cell restriction.