as fierce as pelican bay's mainline housing can be, there is a place that inmates fear even more. in prison slang, it's known as "the hole." while pelican bay houses some of the worst inmate the state of california, the security housing unit or shu has always housed the worst inmates in pelican bay. >> now this might look concrete to you, but it is not comparison to the shu program. everything is concrete. >> no ground, no grass, it is all cement. lights all the time. noisy. the yard, you look up at the roof and it is like this. you don't see the sky, you still see bars, you know what i mean? >> you know, you can drive yourself crazy like that just sitting somewhere for 23 hours a day. i wouldn't want to see my worst enemy go back there. it's no place for any human being. >> in addition to containing inmates with a history of violence in the general population, the shu houses inmates who have been officially