As international leaders fear what Pyongyang may do beyond its borders, perhaps the biggest issue is what happens within. North Korea operates a growing network of prison camps containing up to 200,000 prisoners in conditions likened by survivors to Nazi concentration camps. This atrocity gains little international attention, though the United Nations Human Rights Council is considering a formal inquiry for possible crimes against humanity. Information about the camps is limited to reports from the few successful escapees, notably Shin Dong-hyuk, who told 60 Minutes about spending 23 years behind the wire. North Korea's prison camps are a closed-off world of death, torture and forced labour where babies are born slaves, according to two survivors who liken the horrors of the camps to a Holocaust in progress.