Located on an Appalachian mountaintop in Wise County, Va., Red Onion State Prison is a “supermax” facility built to house individual inmates in 8’x10’ solitary-confinement cells, 23 hours a day, for months, years and sometimes decades. Directed by Kristi Jacobson, Solitary: Inside Red Onion State Prison explores life on both sides of the bars, raising provocative questions about punishment in America today. (HBO)