A look behind the scenes at some of the country's most secure prisons and how inmates are passing drugs, weapons and deadly orders.
Behind the big electric fence at one Colorado prison, inmates have resorted to classic convict behaviour. Gangs and other illegal activities flourish here, posing serious problems for officers.
Nuevo Laredo lies just a few miles south of the US-Mexico border, across the Rio Grande from Laredo, Texas. It's a major hot spot in the drug war - a border town known for its chilling violence and rampant corruption. And it's the perfect home for a notorious Mexican prison known as Cedes.
Meet the officers trying to protect Cuyahoga County Jail from the spread of the Heartless Felons – one of Ohio's deadliest prison gangs.
Go inside one of America’s most dangerous prisons where hardened criminals may be female, but it's just as difficult to keep them in line.